{
 "paper": {
  "school": "Nan Hua Primary School",
  "year": 2025,
  "level": "P4",
  "label": "End-of-Year Exam",
  "source_prefix": "Nan Hua 2025 P4 End-of-Year Exam",
  "has_answer_key": true
 },
 "questions": [
  {
   "n": 1,
   "type_id": 1,
   "question": "Complete the number pattern.<br>8, 14, 20, ____________, ____________, 38",
   "answer0": "21, 22",
   "answer1": "21, 37",
   "answer2": "26, 27",
   "answer3": "26, 32",
   "correct_answer": 3,
   "skill_id": 108,
   "difficulty_id": 1,
   "explanation": "The pattern increases by 6 each time: 8, 14, 20, 26, 32, 38. The two missing numbers are 26 and 32.",
   "hints": [
    "Find the difference between consecutive terms: 14 - 8 = 6.",
    "Keep adding 6: 20 + 6 = 26, 26 + 6 = 32."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q1",
   "image_needed": false,
   "image_options": false,
   "image_file": null,
   "notes": ""
  },
  {
   "n": 2,
   "type_id": 1,
   "question": "34 762 rounded to the nearest hundred is ____________.",
   "answer0": "34 700",
   "answer1": "34 760",
   "answer2": "34 800",
   "answer3": "35 000",
   "correct_answer": 2,
   "skill_id": 109,
   "difficulty_id": 1,
   "explanation": "Look at the tens digit (6). Since 6 is 5 or more, round the hundreds up: 34 762 rounds to 34 800.",
   "hints": [
    "The hundreds digit is 7; the digit after it (tens) is 6.",
    "6 is 5 or more, so round up to 34 800."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q2",
   "image_needed": false,
   "image_options": false,
   "image_file": null,
   "notes": ""
  },
  {
   "n": 3,
   "type_id": 1,
   "question": "In 56.87, the digit ____________ is in the tenths place.",
   "answer0": "5",
   "answer1": "6",
   "answer2": "7",
   "answer3": "8",
   "correct_answer": 3,
   "skill_id": 123,
   "difficulty_id": 1,
   "explanation": "The first digit after the decimal point is the tenths place. In 56.87 that digit is 8.",
   "hints": [
    "The first place after the decimal point is the tenths.",
    "In 56.87, the digit just after the point is 8."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q3",
   "image_needed": false,
   "image_options": false,
   "image_file": null,
   "notes": ""
  },
  {
   "n": 4,
   "type_id": 1,
   "question": "What fraction of the shapes are stars?",
   "answer0": "$$\\frac{5}{12}$$",
   "answer1": "$$\\frac{5}{7}$$",
   "answer2": "$$\\frac{7}{12}$$",
   "answer3": "$$\\frac{7}{5}$$",
   "correct_answer": 0,
   "skill_id": 120,
   "difficulty_id": 1,
   "explanation": "There are 12 shapes in all and 5 of them are stars (3 in the top row and 2 in the bottom row). So the fraction is $$\\frac{5}{12}$$.",
   "hints": [
    "Count the total number of shapes.",
    "Count how many are stars, then write stars over total."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q4",
   "image_needed": true,
   "image_options": false,
   "image_file": "q4.png",
   "image_page": 3,
   "image_bbox": [
    0.3,
    0.17,
    0.58,
    0.26
   ],
   "image_loc": "boxed row of stars and smiley faces, just below the question stem",
   "notes": "5 stars out of 12 shapes."
  },
  {
   "n": 5,
   "type_id": 1,
   "question": "Arrange these fractions from the smallest to the greatest.<br>$$\\frac{5}{9}$$, $$\\frac{1}{2}$$, $$\\frac{8}{9}$$",
   "answer0": "$$\\frac{1}{2}$$, $$\\frac{5}{9}$$, $$\\frac{8}{9}$$",
   "answer1": "$$\\frac{5}{9}$$, $$\\frac{1}{2}$$, $$\\frac{8}{9}$$",
   "answer2": "$$\\frac{8}{9}$$, $$\\frac{5}{9}$$, $$\\frac{1}{2}$$",
   "answer3": "$$\\frac{5}{9}$$, $$\\frac{8}{9}$$, $$\\frac{1}{2}$$",
   "correct_answer": 0,
   "skill_id": 79,
   "difficulty_id": 2,
   "explanation": "Convert to a common denominator of 18: $$\\frac{1}{2}=\\frac{9}{18}$$, $$\\frac{5}{9}=\\frac{10}{18}$$, $$\\frac{8}{9}=\\frac{16}{18}$$. Smallest to greatest: $$\\frac{1}{2}$$, $$\\frac{5}{9}$$, $$\\frac{8}{9}$$.",
   "hints": [
    "Use a common denominator such as 18 to compare.",
    "9/18 < 10/18 < 16/18."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q5",
   "image_needed": false,
   "image_options": false,
   "image_file": null,
   "notes": ""
  },
  {
   "n": 6,
   "type_id": 1,
   "question": "Which angle is smaller than a right angle?",
   "answer0": "$$\\angle a$$",
   "answer1": "$$\\angle b$$",
   "answer2": "$$\\angle c$$",
   "answer3": "$$\\angle d$$",
   "correct_answer": 3,
   "skill_id": 99,
   "difficulty_id": 2,
   "explanation": "Comparing each marked angle to a right angle (90 degrees), angle d is the only one that is acute (smaller than a right angle).",
   "hints": [
    "A right angle is a square corner (90 degrees).",
    "An angle smaller than a right angle is acute (sharp)."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q6",
   "image_needed": true,
   "image_options": false,
   "image_file": "q6.png",
   "image_page": 4,
   "image_bbox": [
    0.35,
    0.14,
    0.58,
    0.3
   ],
   "image_loc": "quadrilateral figure with angles a, b, c, d labelled, to the right of the options",
   "notes": "Answer is angle d."
  },
  {
   "n": 7,
   "type_id": 1,
   "question": "How many pair(s) of parallel lines are there in the figure?",
   "answer0": "1",
   "answer1": "2",
   "answer2": "3",
   "answer3": "4",
   "correct_answer": 1,
   "skill_id": 100,
   "difficulty_id": 2,
   "explanation": "Examining the lines drawn on the grid, there are 2 pairs of parallel lines.",
   "hints": [
    "Parallel lines never meet and stay the same distance apart.",
    "Use the grid squares to check which line segments run in the same direction."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q7",
   "image_needed": true,
   "image_options": false,
   "image_file": "q7.png",
   "image_page": 4,
   "image_bbox": [
    0.39,
    0.34,
    0.6,
    0.46
   ],
   "image_loc": "square grid with line segments forming an arrow-like figure, below the question",
   "notes": "Answer is 2 pairs."
  },
  {
   "n": 8,
   "type_id": 1,
   "question": "Mr Andrew bought 10 $$l$$ of paint. He used 0.55 $$l$$ of the paint on a door and 3.82 $$l$$ of the paint on the walls of a bedroom. How much paint had he left?",
   "answer0": "4.37 $$l$$",
   "answer1": "5.63 $$l$$",
   "answer2": "6.18 $$l$$",
   "answer3": "6.37 $$l$$",
   "correct_answer": 1,
   "skill_id": 131,
   "difficulty_id": 2,
   "explanation": "Total used = 0.55 + 3.82 = 4.37 l. Paint left = 10 - 4.37 = 5.63 l.",
   "hints": [
    "First add the two amounts of paint used.",
    "Subtract the total used from 10 l."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q8",
   "image_needed": false,
   "image_options": false,
   "image_file": null,
   "notes": ""
  },
  {
   "n": 9,
   "type_id": 1,
   "question": "Which of the following geometric figures shows a cuboid?",
   "answer0": "Figure 1 (cylinder)",
   "answer1": "Figure 2 (pyramid)",
   "answer2": "Figure 3 (hexagonal prism)",
   "answer3": "Figure 4 (cuboid)",
   "correct_answer": 3,
   "skill_id": 231,
   "difficulty_id": 1,
   "explanation": "A cuboid is a box shape with 6 rectangular faces. Figure 4 is the cuboid.",
   "hints": [
    "A cuboid is like a rectangular box.",
    "It has 6 flat rectangular faces."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q9",
   "image_needed": true,
   "image_options": true,
   "image_file": null,
   "image_page": 5,
   "image_bbox": [
    0.18,
    0.18,
    0.82,
    0.3
   ],
   "image_loc": "four 3D solid figures in a row labelled (1) to (4)",
   "notes": "Image-option MCQ: crop each solid to q9_opt0.png ... q9_opt3.png. (1) cylinder, (2) pyramid, (3) hexagonal prism, (4) cuboid. Answer is option (4)."
  },
  {
   "n": 10,
   "type_id": 1,
   "question": "Macy had 5 m of string at first. She used $$\\frac{11}{12}$$ m of string to make a kite. How much string did she have left?",
   "answer0": "$$\\frac{1}{12}$$ m",
   "answer1": "$$\\frac{11}{12}$$ m",
   "answer2": "$$4\\frac{1}{12}$$ m",
   "answer3": "$$4\\frac{11}{12}$$ m",
   "correct_answer": 2,
   "skill_id": 122,
   "difficulty_id": 2,
   "explanation": "5 - $$\\frac{11}{12}$$ = $$4\\frac{12}{12}$$ - $$\\frac{11}{12}$$ = $$4\\frac{1}{12}$$ m.",
   "hints": [
    "Rename 5 as $$4\\frac{12}{12}$$ before subtracting.",
    "$$\\frac{12}{12} - \\frac{11}{12} = \\frac{1}{12}$$."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q10",
   "image_needed": false,
   "image_options": false,
   "image_file": null,
   "notes": ""
  },
  {
   "n": 11,
   "type_id": 1,
   "question": "Which of the following is not a net of a pyramid?",
   "answer0": "Net 1",
   "answer1": "Net 2",
   "answer2": "Net 3",
   "answer3": "Net 4",
   "correct_answer": 1,
   "skill_id": 232,
   "difficulty_id": 2,
   "explanation": "A pyramid net has one polygon base with triangular faces folding up to a point. Net 2 cannot fold into a pyramid, so it is not a net of a pyramid.",
   "hints": [
    "A pyramid net has one base and triangles around it.",
    "Check which net would not close up into a single apex."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q11",
   "image_needed": true,
   "image_options": true,
   "image_file": null,
   "image_page": 5,
   "image_bbox": [
    0.18,
    0.65,
    0.82,
    0.82
   ],
   "image_loc": "four nets in a row labelled (1) to (4) near the bottom of the page",
   "notes": "Image-option MCQ: crop each net to q11_opt0.png ... q11_opt3.png. Answer is option (2)."
  },
  {
   "n": 12,
   "type_id": 1,
   "question": "The graph shows the amount of money spent by Janet from Monday to Friday.<br>How much more money did Janet spend on Friday than on Wednesday?",
   "answer0": "$3.80",
   "answer1": "$3.90",
   "answer2": "$4.80",
   "answer3": "$4.90",
   "correct_answer": 0,
   "skill_id": 104,
   "difficulty_id": 2,
   "explanation": "From the graph, Friday = $5.00 and Wednesday = $1.20. Difference = 5.00 - 1.20 = $3.80.",
   "hints": [
    "Read the Friday and Wednesday bars from the graph.",
    "Subtract the Wednesday amount from the Friday amount."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q12",
   "image_needed": true,
   "image_options": false,
   "image_file": "q12.png",
   "image_page": 6,
   "image_bbox": [
    0.22,
    0.17,
    0.84,
    0.43
   ],
   "image_loc": "bar graph 'Amount of money spent' over Days of the week, top of page (shared by Q12 and Q13)",
   "notes": "Friday $5.00, Wednesday $1.20. Same graph used for Q13."
  },
  {
   "n": 13,
   "type_id": 1,
   "question": "Janet's weekly allowance was $40. How much had she left at the end of the week?",
   "answer0": "$21.80",
   "answer1": "$21.20",
   "answer2": "$20.20",
   "answer3": "$19.80",
   "correct_answer": 2,
   "skill_id": 104,
   "difficulty_id": 2,
   "explanation": "Total spent = 2.50 + 3.00 + 1.20 + 8.00 + 5.00 = $19.80. Left = 40 - 19.80 = $20.20.",
   "hints": [
    "Add up the amount spent on all five days from the graph.",
    "Subtract the total spent from $40."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q13",
   "image_needed": true,
   "image_options": false,
   "image_file": "q12.png",
   "image_page": 6,
   "image_bbox": [
    0.22,
    0.17,
    0.84,
    0.43
   ],
   "image_loc": "uses the same bar graph as Q12 (top of page 6)",
   "notes": "Mon 2.50, Tue 3.00, Wed 1.20, Thu 8.00, Fri 5.00; total 19.80. Reuses Q12 graph image."
  },
  {
   "n": 14,
   "type_id": 1,
   "question": "Mr Tan has some pencils. The number of pencils can be shared equally among 4 or 7 children without remainder. It has 8 as one of its factors. How many pencils does Mr Tan have?",
   "answer0": "14",
   "answer1": "28",
   "answer2": "40",
   "answer3": "56",
   "correct_answer": 3,
   "skill_id": 115,
   "difficulty_id": 3,
   "explanation": "The number must be divisible by 4, by 7, and have 8 as a factor. 56 is divisible by 4 (56÷4=14), by 7 (56÷7=8) and by 8 (56÷8=7). So Mr Tan has 56 pencils.",
   "hints": [
    "The number must be a common multiple of 4 and 7.",
    "It must also be divisible by 8; check 56."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q14",
   "image_needed": false,
   "image_options": false,
   "image_file": null,
   "notes": ""
  },
  {
   "n": 15,
   "type_id": 1,
   "question": "A field was built on a rectangular plot of land. The plot of land measured 50 m by 34 m. A 2 m wide pavement was built all around the field. What was the area of the pavement?",
   "answer0": "164 m²",
   "answer1": "320 m²",
   "answer2": "336 m²",
   "answer3": "1380 m²",
   "correct_answer": 1,
   "skill_id": 138,
   "difficulty_id": 3,
   "explanation": "Whole plot area = 50 × 34 = 1700 m². The inner field is 2 m narrower on each side: (50 - 4) × (34 - 4) = 46 × 30 = 1380 m². Pavement = 1700 - 1380 = 320 m².",
   "hints": [
    "Find the area of the whole plot first.",
    "The field is 4 m shorter in each dimension (2 m on both sides). Subtract the field area."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q15",
   "image_needed": true,
   "image_options": false,
   "image_file": "q15.png",
   "image_page": 7,
   "image_bbox": [
    0.32,
    0.4,
    0.74,
    0.58
   ],
   "image_loc": "shaded rectangle showing 'field' with 2 m pavement border, 50 m by 34 m, middle of page",
   "notes": ""
  },
  {
   "n": 16,
   "type_id": 1,
   "question": "The total mass of a bottle of milk and two identical cartons of apple juice is as shown. The mass of the carton of milk is three times as heavy as one carton of apple juice. Find the mass of the carton of milk.",
   "answer0": "1075 g",
   "answer1": "1720 g",
   "answer2": "2580 g",
   "answer3": "3225 g",
   "correct_answer": 2,
   "skill_id": 118,
   "difficulty_id": 3,
   "explanation": "From the scale the total mass is 4300 g. Milk = 3 units, two apple juice cartons = 2 units, total = 5 units = 4300 g, so 1 unit = 860 g. Milk = 3 × 860 = 2580 g.",
   "hints": [
    "Let one carton of apple juice be 1 unit; the milk is 3 units.",
    "Total = 3 + 2 = 5 units. Read the total off the scale, divide by 5, then multiply by 3."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q16",
   "image_needed": true,
   "image_options": false,
   "image_file": "q16.png",
   "image_page": 8,
   "image_bbox": [
    0.62,
    0.18,
    0.88,
    0.38
   ],
   "image_loc": "weighing scale with a MILK bottle and two APPLE JUICE cartons, right side of question",
   "notes": "Scale reads total 4300 g. 5 units = 4300, milk = 3 units = 2580 g."
  },
  {
   "n": 17,
   "type_id": 1,
   "question": "Alan and Brian had an equal number of marbles at first. After Alan bought 36 more marbles and Brian gave away 24 marbles, Alan had 4 times as many marbles as Brian. How many marbles did each of them have at first?",
   "answer0": "20",
   "answer1": "39",
   "answer2": "44",
   "answer3": "80",
   "correct_answer": 2,
   "skill_id": 118,
   "difficulty_id": 3,
   "explanation": "Let each start with x. Alan now = x + 36, Brian now = x - 24. x + 36 = 4(x - 24) → x + 36 = 4x - 96 → 132 = 3x → x = 44. Each had 44 marbles at first.",
   "hints": [
    "Write Alan's new amount as (start + 36) and Brian's as (start - 24).",
    "Alan = 4 × Brian; solve for the starting amount."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q17",
   "image_needed": false,
   "image_options": false,
   "image_file": null,
   "notes": ""
  },
  {
   "n": 18,
   "type_id": 1,
   "question": "Mrs Tan has a piece of ribbon 4 m long. She cuts 5 equal pieces from the ribbon and has 75 cm left. What is the length of each of the 5 pieces of ribbon?",
   "answer0": "5 cm",
   "answer1": "65 cm",
   "answer2": "725 cm",
   "answer3": "785 cm",
   "correct_answer": 1,
   "skill_id": 118,
   "difficulty_id": 2,
   "explanation": "4 m = 400 cm. Ribbon used for 5 pieces = 400 - 75 = 325 cm. Each piece = 325 ÷ 5 = 65 cm.",
   "hints": [
    "Change 4 m to centimetres first.",
    "Subtract the 75 cm left, then divide by 5."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q18",
   "image_needed": false,
   "image_options": false,
   "image_file": null,
   "notes": ""
  },
  {
   "n": 19,
   "type_id": 1,
   "question": "Which of the following are nets of a cube?",
   "answer0": "A and B only",
   "answer1": "A and C only",
   "answer2": "B and C only",
   "answer3": "A, B and C",
   "correct_answer": 0,
   "skill_id": 232,
   "difficulty_id": 2,
   "explanation": "Nets A and B fold into a cube; net C does not. So the answer is A and B only.",
   "hints": [
    "A cube net has 6 squares that fold without overlapping.",
    "Mentally fold each net to see which form a closed cube."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q19",
   "image_needed": true,
   "image_options": false,
   "image_file": "q19.png",
   "image_page": 9,
   "image_bbox": [
    0.48,
    0.15,
    0.92,
    0.27
   ],
   "image_loc": "three nets labelled A, B, C to the right of the options",
   "notes": "Answer A and B only. Figure shows nets A, B, C."
  },
  {
   "n": 20,
   "type_id": 1,
   "question": "The graph records the growth of a plant from January to May.<br>In which period was the increase in the plant's height the smallest?",
   "answer0": "January to February",
   "answer1": "February to March",
   "answer2": "March to April",
   "answer3": "April to May",
   "correct_answer": 3,
   "skill_id": 147,
   "difficulty_id": 2,
   "explanation": "Read the height at each month and find the smallest rise. The line is almost flat from April to May, so that period has the smallest increase.",
   "hints": [
    "Compare how much the line rises in each one-month period.",
    "The flattest part of the line is the smallest increase."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q20",
   "image_needed": true,
   "image_options": false,
   "image_file": "q20.png",
   "image_page": 9,
   "image_bbox": [
    0.2,
    0.36,
    0.82,
    0.58
   ],
   "image_loc": "line graph 'Height of Plant (cm)' against Months, below the question",
   "notes": "Answer April to May (line flattest)."
  },
  {
   "n": 21,
   "type_id": 2,
   "question": "Write fifteen thousand and twenty-five in numerals.<br>[?]",
   "answer0": "15025",
   "answer1": null,
   "answer2": null,
   "answer3": null,
   "correct_answer": null,
   "skill_id": 106,
   "difficulty_id": 1,
   "explanation": "Fifteen thousand = 15 000; twenty-five = 25. Together: 15 025.",
   "hints": [
    "Fifteen thousand is 15 000.",
    "Add twenty-five: 15 000 + 25 = 15 025."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q21",
   "image_needed": false,
   "image_options": false,
   "image_file": null,
   "notes": "Answer key: 15 025."
  },
  {
   "n": 22,
   "type_id": 2,
   "question": "4729 + 1585 = [?]",
   "answer0": "6314",
   "answer1": null,
   "answer2": null,
   "answer3": null,
   "correct_answer": null,
   "skill_id": 116,
   "difficulty_id": 1,
   "explanation": "4729 + 1585 = 6314.",
   "hints": [
    "Add the ones, tens, hundreds and thousands in columns.",
    "Remember to carry where needed."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q22",
   "image_needed": false,
   "image_options": false,
   "image_file": null,
   "notes": "Answer key: 6314."
  },
  {
   "n": 23,
   "type_id": 2,
   "question": "Two factors of 10 are 1 and 10. What are the other two factors of 10?<br>[?] and [?]",
   "answer0": "2",
   "answer1": "5",
   "answer2": null,
   "answer3": null,
   "correct_answer": null,
   "skill_id": 111,
   "difficulty_id": 1,
   "explanation": "10 = 2 × 5, so the other two factors of 10 are 2 and 5.",
   "hints": [
    "Factors of 10 are numbers that divide 10 exactly.",
    "10 = 2 × 5."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q23",
   "image_needed": false,
   "image_options": false,
   "image_file": null,
   "notes": "Answer key: 2 and 5 (order interchangeable)."
  },
  {
   "n": 24,
   "type_id": 2,
   "question": "$$\\frac{5}{6} = \\frac{[?]}{12}$$<br>What is the missing number in the box?",
   "answer0": "10",
   "answer1": null,
   "answer2": null,
   "answer3": null,
   "correct_answer": null,
   "skill_id": 80,
   "difficulty_id": 1,
   "explanation": "Multiply numerator and denominator of $$\\frac{5}{6}$$ by 2: $$\\frac{5 \\times 2}{6 \\times 2} = \\frac{10}{12}$$. The missing number is 10.",
   "hints": [
    "6 × 2 = 12, so multiply the numerator by 2 as well.",
    "5 × 2 = 10."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q24",
   "image_needed": false,
   "image_options": false,
   "image_file": null,
   "notes": "Answer key: 10."
  },
  {
   "n": 25,
   "type_id": 2,
   "question": "$$1 - \\frac{1}{8} - \\frac{1}{4}$$ = [?]",
   "answer0": "5/8",
   "answer1": null,
   "answer2": null,
   "answer3": null,
   "correct_answer": null,
   "skill_id": 121,
   "difficulty_id": 2,
   "explanation": "Change all to eighths: $$\\frac{8}{8} - \\frac{1}{8} - \\frac{2}{8} = \\frac{5}{8}$$.",
   "hints": [
    "Write 1 as $$\\frac{8}{8}$$ and $$\\frac{1}{4}$$ as $$\\frac{2}{8}$$.",
    "Subtract: 8 - 1 - 2 = 5 eighths."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q25",
   "image_needed": false,
   "image_options": false,
   "image_file": null,
   "notes": "Answer key: 5/8."
  },
  {
   "n": 26,
   "type_id": 2,
   "question": "Express $$\\frac{85}{100}$$ as a decimal.<br>[?]",
   "answer0": "0.85",
   "answer1": null,
   "answer2": null,
   "answer3": null,
   "correct_answer": null,
   "skill_id": 127,
   "difficulty_id": 1,
   "explanation": "$$\\frac{85}{100}$$ means 85 hundredths = 0.85.",
   "hints": [
    "Hundredths take two decimal places.",
    "85 hundredths = 0.85."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q26",
   "image_needed": false,
   "image_options": false,
   "image_file": null,
   "notes": "Answer key: 0.85."
  },
  {
   "n": 27,
   "type_id": 2,
   "question": "4.36 + 2 = [?]",
   "answer0": "6.36",
   "answer1": null,
   "answer2": null,
   "answer3": null,
   "correct_answer": null,
   "skill_id": 129,
   "difficulty_id": 1,
   "explanation": "Add the whole numbers: 4.36 + 2 = 6.36.",
   "hints": [
    "Add 2 to the whole-number part.",
    "The decimal part stays 0.36."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q27",
   "image_needed": false,
   "image_options": false,
   "image_file": null,
   "notes": "Answer key: 6.36."
  },
  {
   "n": 28,
   "type_id": 2,
   "question": "Find the value of 2.63 × 8.<br>[?]",
   "answer0": "21.04",
   "answer1": null,
   "answer2": null,
   "answer3": null,
   "correct_answer": null,
   "skill_id": 130,
   "difficulty_id": 2,
   "explanation": "2.63 × 8 = 21.04 (263 × 8 = 2104, then place the decimal point two places: 21.04).",
   "hints": [
    "Multiply 263 × 8 first, ignoring the decimal point.",
    "263 × 8 = 2104, so 2.63 × 8 = 21.04."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q28",
   "image_needed": false,
   "image_options": false,
   "image_file": null,
   "notes": "Answer key: 21.04."
  },
  {
   "n": 29,
   "type_id": 2,
   "question": "ABCD is a rectangle. Find $$\\angle x$$.<br>[?]",
   "answer0": "35",
   "answer1": null,
   "answer2": null,
   "answer3": null,
   "correct_answer": null,
   "skill_id": 230,
   "difficulty_id": 2,
   "explanation": "Angle B of the rectangle is a right angle (90 degrees). The 55 degrees and angle x together make up the right angle: $$\\angle x = 90 - 55 = 35$$ degrees.",
   "hints": [
    "The corner of a rectangle is 90 degrees.",
    "Subtract the marked 55 degrees from 90 degrees."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q29",
   "image_needed": true,
   "image_options": false,
   "image_file": "q29.png",
   "image_page": 12,
   "image_bbox": [
    0.2,
    0.14,
    0.42,
    0.24
   ],
   "image_loc": "rectangle ABCD with a diagonal line from B, 55 degrees and x marked at corner B, below the question",
   "notes": "Answer key: 35 degrees. Answer is in degrees (unit shown on paper)."
  },
  {
   "n": 30,
   "type_id": 0,
   "question": "In the figure, line AB is a line of symmetry. Shade the least number of unit square(s) to make the figure symmetric.",
   "answer0": null,
   "answer1": null,
   "answer2": null,
   "answer3": null,
   "correct_answer": null,
   "skill_id": 145,
   "difficulty_id": 2,
   "explanation": "Reflect each already-shaded square across the diagonal line of symmetry AB and shade its mirror square; shade the least number of squares needed so the figure is symmetric about AB.",
   "hints": [
    "Reflect each shaded square across the dashed line AB.",
    "Shade only the mirror squares that are not already shaded."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q30",
   "image_needed": true,
   "image_options": false,
   "image_file": "q30.png",
   "image_page": 12,
   "image_bbox": [
    0.18,
    0.4,
    0.52,
    0.62
   ],
   "image_loc": "grid with shaded squares and a dashed diagonal line of symmetry from B to A, below the question",
   "notes": "Interactive shading (colour/draw) task — no value answer, type_id 0. Skipped on insert."
  },
  {
   "n": 31,
   "type_id": 2,
   "question": "92 tenths − 48 hundredths. Express your answer as a decimal.<br>[?]",
   "answer0": "8.72",
   "answer1": null,
   "answer2": null,
   "answer3": null,
   "correct_answer": null,
   "skill_id": 129,
   "difficulty_id": 2,
   "explanation": "92 tenths = 9.2 and 48 hundredths = 0.48. 9.2 - 0.48 = 8.72.",
   "hints": [
    "92 tenths = 9.2; 48 hundredths = 0.48.",
    "Subtract: 9.2 - 0.48 = 8.72."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q31",
   "image_needed": false,
   "image_options": false,
   "image_file": null,
   "notes": "Answer key: 8.72."
  },
  {
   "n": 32,
   "type_id": 0,
   "question": "The table shows the number of books borrowed by the students in Class 4M. A total of 71 books were borrowed. Each statement is either true, false or not possible to tell from the information given. For each statement, tick the correct column.",
   "answer0": null,
   "answer1": null,
   "answer2": null,
   "answer3": null,
   "correct_answer": null,
   "skill_id": 146,
   "difficulty_id": 3,
   "explanation": "Missing number of students who borrowed 2 books: total books = 71 = 0×5 + 1×12 + 2×? + 3×7 + 4×6 = 12 + 2? + 21 + 24, so 2? = 14, ? = 7. Statement 1 '20 students borrowed at least 2 books each' (7+7+6=20) is True. Statement 2 'More than half the class borrowed only 1 book' — class size = 5+12+7+7+6 = 37, half is 18.5; only 12 borrowed 1 book, so False. Statement 3 'The 5 students who did not borrow any books borrowed at least 1 each, total became 76' — they could borrow more than 1 each, so it is Not possible to tell.",
   "hints": [
    "First find the missing frequency using the total of 71 books.",
    "Check each statement against the completed table."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q32",
   "image_needed": true,
   "image_options": false,
   "image_file": "q32.png",
   "image_page": 13,
   "image_bbox": [
    0.18,
    0.18,
    0.84,
    0.25
   ],
   "image_loc": "frequency table 'Number of books borrowed' vs 'Number of students', below the first line of the question",
   "notes": "Tick-the-column task — no single value answer, type_id 0 (skipped on insert). Key: True / False / Not possible to tell. Missing frequency = 7."
  },
  {
   "n": 33,
   "type_id": 2,
   "question": "Nadim completed his homework at 11 25. He took 1 h 45 min to complete his homework. What time did Nadim start doing his homework? Express your answer in 24-hour clock.<br>[?]",
   "answer0": "0940",
   "answer1": null,
   "answer2": null,
   "answer3": null,
   "correct_answer": null,
   "skill_id": 135,
   "difficulty_id": 2,
   "explanation": "Work backwards from 1125. Subtract 1 h to get 1025, then subtract 45 min to get 0940. Nadim started at 0940.",
   "hints": [
    "Subtract the duration from the finishing time.",
    "1125 minus 1 h = 1025; 1025 minus 45 min = 0940."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q33",
   "image_needed": false,
   "image_options": false,
   "image_file": null,
   "notes": "Answer key (timeline): 0940."
  },
  {
   "n": 34,
   "type_id": 2,
   "question": "Mrs Lee bought a papaya and a durian. The mass of the papaya was $$\\frac{9}{10}$$ kg. It was $$\\frac{1}{2}$$ kg lighter than the mass of the durian. What was the mass of the durian? Express your answer as a mixed number in its simplest form.<br>[?] kg",
   "answer0": "1 2/5",
   "answer1": null,
   "answer2": null,
   "answer3": null,
   "correct_answer": null,
   "skill_id": 122,
   "difficulty_id": 2,
   "explanation": "Durian = papaya + $$\\frac{1}{2}$$ = $$\\frac{9}{10} + \\frac{1}{2} = \\frac{9}{10} + \\frac{5}{10} = \\frac{14}{10} = 1\\frac{4}{10} = 1\\frac{2}{5}$$ kg.",
   "hints": [
    "The papaya is lighter, so the durian = papaya + $$\\frac{1}{2}$$ kg.",
    "Use a common denominator of 10, then simplify the mixed number."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q34",
   "image_needed": false,
   "image_options": false,
   "image_file": null,
   "notes": "Answer key: 1 2/5 kg. Student types mixed number as 1 2/5."
  },
  {
   "n": 35,
   "type_id": 2,
   "question": "The capacity of a tank is 12 $$l$$. There is 875 m$$l$$ of water in the tank. How much water must be added to fill the tank completely? Give your answer in litres and millilitres.<br>[?] $$l$$ [?] m$$l$$",
   "answer0": "11",
   "answer1": "125",
   "answer2": null,
   "answer3": null,
   "correct_answer": null,
   "skill_id": 87,
   "difficulty_id": 2,
   "explanation": "875 ml = 0.875 l. Water needed = 12 - 0.875 = 11.125 l = 11 l 125 ml.",
   "hints": [
    "Convert the capacity and current amount to the same unit.",
    "12 l - 875 ml = 11 l 125 ml (since 1000 ml - 875 ml = 125 ml)."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q35",
   "image_needed": false,
   "image_options": false,
   "image_file": null,
   "notes": "Answer key: 11 l 125 ml. Two blanks: litres then millilitres."
  },
  {
   "n": 36,
   "type_id": 2,
   "question": "In the number line, (a) what is the mixed number represented by A? (b) what is the improper fraction represented by B?<br>[?]<br>[?]",
   "answer0": "1 1/6",
   "answer1": "11/6",
   "answer2": null,
   "answer3": null,
   "correct_answer": null,
   "skill_id": 119,
   "difficulty_id": 2,
   "explanation": "Each interval between whole numbers is divided into sixths. A is one-sixth past 1, so A = $$1\\frac{1}{6}$$. B is five-sixths past 1 (one-sixth before 2), which as an improper fraction is $$\\frac{11}{6}$$.",
   "hints": [
    "Count how many equal parts each whole number is split into.",
    "A is just past 1; B is just before 2. Convert B to an improper fraction."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q36",
   "image_needed": true,
   "image_options": false,
   "image_file": "q36.png",
   "image_page": 15,
   "image_bbox": [
    0.16,
    0.15,
    0.8,
    0.26
   ],
   "image_loc": "number line from 1/2 to 2 with arrows marking points A and B, below the question",
   "notes": "Answer key: (a) 1 1/6, (b) 11/6. Two blanks: part (a) mixed number, part (b) improper fraction."
  },
  {
   "n": 37,
   "type_id": 0,
   "question": "Draw $$\\angle ABC = 85^\\circ$$ with the given line AB. Mark and label the angle.",
   "answer0": null,
   "answer1": null,
   "answer2": null,
   "answer3": null,
   "correct_answer": null,
   "skill_id": 140,
   "difficulty_id": 2,
   "explanation": "Using a protractor, place the centre at B on line AB, measure 85 degrees, and draw ray BC. Mark and label the 85-degree angle ABC.",
   "hints": [
    "Place the protractor centre on point B along line AB.",
    "Measure 85 degrees and draw the ray, then label the angle."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q37",
   "image_needed": true,
   "image_options": false,
   "image_file": "q37.png",
   "image_page": 15,
   "image_bbox": [
    0.22,
    0.74,
    0.58,
    0.8
   ],
   "image_loc": "given line segment AB near the bottom of the page",
   "notes": "Construction/drawing task — no value answer, type_id 0 (skipped on insert)."
  },
  {
   "n": 38,
   "type_id": 0,
   "question": "The graph represents the number of people at a carnival. The information is also represented by a pie chart. Label the pie chart by writing M for men, W for women, B for boys and G for girls in the blanks.",
   "answer0": null,
   "answer1": null,
   "answer2": null,
   "answer3": null,
   "correct_answer": null,
   "skill_id": 235,
   "difficulty_id": 3,
   "explanation": "From the bar graph: Girls 70 (largest), Women 60, Men 40, Boys 30 (smallest). The largest pie slice is Girls, next Women, then Men, then the smallest is Boys. Per the key: (a) G, (b) M, (c) W, (d) B.",
   "hints": [
    "Read each group's value from the bar graph and rank them by size.",
    "Match the biggest slice to the biggest group."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q38",
   "image_needed": true,
   "image_options": false,
   "image_file": "q38.png",
   "image_page": 16,
   "image_bbox": [
    0.18,
    0.16,
    0.74,
    0.36
   ],
   "image_loc": "horizontal bar graph 'People at a carnival' (Girls, Boys, Women, Men) plus the unlabelled pie chart below it",
   "notes": "Label-the-pie-chart (write-in-blanks) task — no single value answer, type_id 0 (skipped on insert). Key labels: (a) G, (b) M, (c) W, (d) B. Bar graph values Girls 70, Women 60, Men 40, Boys 30."
  },
  {
   "n": 39,
   "type_id": 2,
   "question": "The figure is made up of 2 squares. The sides of the squares are whole numbers. What is the area of the figure?<br>[?] cm²",
   "answer0": "106",
   "answer1": null,
   "answer2": null,
   "answer3": null,
   "correct_answer": null,
   "skill_id": 138,
   "difficulty_id": 3,
   "explanation": "The bigger square's side minus the smaller square's side = 4 cm, and the two sides together span 14 cm. So big − small = 4 and big + small = 14, giving big = 9 cm and small = 5 cm. Area = 9 × 9 + 5 × 5 = 81 + 25 = 106 cm².",
   "hints": [
    "The difference in the two square sides is 4 cm and their total along the base is 14 cm.",
    "Solve to get sides 9 cm and 5 cm, then add the two square areas."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q39",
   "image_needed": true,
   "image_options": false,
   "image_file": "q39.png",
   "image_page": 17,
   "image_bbox": [
    0.26,
    0.16,
    0.5,
    0.27
   ],
   "image_loc": "two overlapping squares with 4 cm height marker and 14 cm base, below the question",
   "notes": "Answer key: 106 cm². Sides 9 cm and 5 cm."
  },
  {
   "n": 40,
   "type_id": 2,
   "question": "The figure is made up of straight lines that meet at right angles. Find its perimeter.<br>[?] cm",
   "answer0": "76",
   "answer1": null,
   "answer2": null,
   "answer3": null,
   "correct_answer": null,
   "skill_id": 138,
   "difficulty_id": 3,
   "explanation": "Using the rectilinear figure, the horizontal sides total to twice the widest horizontal span and the vertical sides total to twice the tallest span. The key gives perimeter = 25 + 18 + 18 + 15 = 76 cm.",
   "hints": [
    "In a rectilinear figure, opposite horizontal segments add to the same total, as do the verticals.",
    "Add the four edge groups: 25 + 18 + 18 + 15 = 76."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q40",
   "image_needed": true,
   "image_options": false,
   "image_file": "q40.png",
   "image_page": 17,
   "image_bbox": [
    0.24,
    0.5,
    0.52,
    0.7
   ],
   "image_loc": "L-shaped rectilinear figure with 18 cm and 5 cm marked and tick marks for equal sides, below the question",
   "notes": "Answer key: 76 cm."
  },
  {
   "n": 41,
   "type_id": 2,
   "question": "David has four times as many stamps as Ethan. Fiona has 60 fewer stamps than David. David, Ethan, and Fiona have a total of 1380 stamps. How many stamps does David have?<br>[?]",
   "answer0": "640",
   "answer1": null,
   "answer2": null,
   "answer3": null,
   "correct_answer": null,
   "skill_id": 118,
   "difficulty_id": 3,
   "explanation": "Let Ethan = 1 unit. David = 4 units. Fiona = 4 units - 60. Total = 1 + 4 + 4 units - 60 = 9 units - 60 = 1380, so 9 units = 1440, 1 unit = 160. David = 4 units = 4 × 160 = 640 stamps.",
   "hints": [
    "Let Ethan be 1 unit; David is 4 units and Fiona is 4 units − 60.",
    "9 units − 60 = 1380. Solve for 1 unit, then find David (4 units)."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q41",
   "image_needed": false,
   "image_options": false,
   "image_file": null,
   "notes": "Answer key: 640 stamps."
  },
  {
   "n": 42,
   "type_id": 2,
   "question": "There were a total of 1785 fiction books and non-fiction books in a library. $$\\frac{2}{7}$$ of the books were non-fiction books and the rest were fiction books. How many more fiction books than non-fiction books were there?<br>[?]",
   "answer0": "765",
   "answer1": null,
   "answer2": null,
   "answer3": null,
   "correct_answer": null,
   "skill_id": 122,
   "difficulty_id": 3,
   "explanation": "Total = 7 units = 1785, so 1 unit = 255. Non-fiction = 2 units, fiction = 5 units. Difference = 5 - 2 = 3 units = 3 × 255 = 765 more fiction books.",
   "hints": [
    "Split the total into 7 equal units; non-fiction is 2 units, fiction is 5 units.",
    "The difference is 3 units. Find 1 unit, then multiply by 3."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q42",
   "image_needed": false,
   "image_options": false,
   "image_file": null,
   "notes": "Answer key: 765 more."
  },
  {
   "n": 43,
   "type_id": 2,
   "question": "Jane bought six identical bowls and five identical plates for $46.90. Mary bought three such bowls and three such plates for $25.20. How much did one plate cost?<br>$$$$[?]",
   "answer0": "3.50",
   "answer1": null,
   "answer2": null,
   "answer3": null,
   "correct_answer": null,
   "skill_id": 118,
   "difficulty_id": 3,
   "explanation": "6 bowls + 5 plates = $46.90. Double Mary's purchase: 6 bowls + 6 plates = 2 × $25.20 = $50.40. Subtract: 1 plate = 50.40 - 46.90 = $3.50.",
   "hints": [
    "Double Mary's amounts so the number of bowls matches Jane's (6 bowls).",
    "6 bowls + 6 plates = $50.40; subtract Jane's 6 bowls + 5 plates to find 1 plate."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q43",
   "image_needed": false,
   "image_options": false,
   "image_file": null,
   "notes": "Answer key: $3.50. Answer typed as 3.50 (dollars)."
  },
  {
   "n": 44,
   "type_id": 2,
   "question": "Three children can sit at each side of a square table. Each time a table is added, it is joined by the side to form a long table. Mdm Lim wants to form a long table that can seat 60 children. How many square tables does she need?<br>[?]",
   "answer0": "9",
   "answer1": null,
   "answer2": null,
   "answer3": null,
   "correct_answer": null,
   "skill_id": 118,
   "difficulty_id": 3,
   "explanation": "The two short ends seat 3 + 3 = 6 children. The long sides seat 60 - 6 = 54 children, 27 on each side. Each table adds 3 seats per long side, so number of tables = 54 ÷ 2 ÷ 3 = 9... per key: 54 ÷ 2 = 27 per side? Using the key's method: 3 × 2 = 6 end seats, 60 - 6 = 54, 54 ÷ 2 = 9 tables (3 children per long side per table on each of 2 sides ⇒ 6 children per table on the long sides; 54 ÷ 6 = 9). She needs 9 square tables.",
   "hints": [
    "The two ends of the long table always seat 3 + 3 = 6 children.",
    "The remaining children sit along the two long sides, 3 per table per side; divide to find the number of tables."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q44",
   "image_needed": true,
   "image_options": false,
   "image_file": "q44.png",
   "image_page": 20,
   "image_bbox": [
    0.18,
    0.18,
    0.84,
    0.3
   ],
   "image_loc": "Figures 1, 2 and 3 showing square tables joined with chairs around them, below the question",
   "notes": "Answer key: 9 square tables (3×2=6 end seats, 60-6=54, 54÷6=9)."
  },
  {
   "n": 45,
   "type_id": 2,
   "question": "The pie chart shows the choices made by a group of children about their favourite snacks. Half of the group likes cookies and brownies. The number of children who like muffins is equal to the number of children who like brownies.<br>(a) What fraction of the students like cookies?<br>(b) Given that 126 children like curry puffs, how many children like muffins?<br>[?]<br>[?]",
   "answer0": "5/12",
   "answer1": "42",
   "answer2": null,
   "answer3": null,
   "correct_answer": null,
   "skill_id": 236,
   "difficulty_id": 3,
   "explanation": "(a) Cupcakes = $$\\frac{1}{6}$$, curry puffs = $$\\frac{1}{4}$$. Muffins = brownies. Cookies + brownies = $$\\frac{1}{2}$$. Muffins = $$\\frac{1}{2} - \\frac{1}{6} - \\frac{1}{4} = \\frac{12}{12} - \\frac{2}{12} - \\frac{3}{12} = \\frac{1}{12}$$ (= brownies). Cookies = $$\\frac{1}{2} - \\frac{1}{12} = \\frac{6}{12} - \\frac{1}{12} = \\frac{5}{12}$$. (b) Curry puffs = $$\\frac{1}{4} = \\frac{3}{12}$$ = 126 children, so 1 unit ($$\\frac{1}{12}$$) = 126 ÷ 3 = 42. Muffins = $$\\frac{1}{12}$$ = 42 children.",
   "hints": [
    "Cupcakes $$\\frac{1}{6}$$ and curry puffs $$\\frac{1}{4}$$; the rest of the half (after cookies+brownies) gives muffins.",
    "Curry puffs $$\\frac{1}{4} = \\frac{3}{12}$$ = 126, so $$\\frac{1}{12}$$ = 42."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q45",
   "image_needed": true,
   "image_options": false,
   "image_file": "q45.png",
   "image_page": 21,
   "image_bbox": [
    0.42,
    0.18,
    0.66,
    0.32
   ],
   "image_loc": "pie chart with sectors Cookies, Brownies, Curry puffs, Cupcakes (1/6), Muffins, between the two question parts",
   "notes": "Answer key: (a) 5/12, (b) 42 muffins. Two blanks: part (a) fraction, part (b) count."
  },
  {
   "n": 46,
   "type_id": 2,
   "question": "Figure 1 shows a rectangular piece of paper, ABCD. WXCY is a square with an area of 9 cm², cut out from the paper as shown in Figure 2. The area of the remaining paper is 261 cm². Given that BX = XC, find the length of AB.<br>[?] cm",
   "answer0": "45",
   "answer1": null,
   "answer2": null,
   "answer3": null,
   "correct_answer": null,
   "skill_id": 136,
   "difficulty_id": 3,
   "explanation": "Square WXCY has area 9 cm², so its side = 3 cm (3 × 3 = 9). Since BX = XC = 3 cm, the side BC = AD = 3 + 3 = 6 cm. Whole rectangle area = remaining + cut-out = 261 + 9 = 270 cm². Length of AB = area ÷ AD = 270 ÷ 6 = 45 cm.",
   "hints": [
    "A square of area 9 cm² has side 3 cm; with BX = XC, side AD = 6 cm.",
    "Whole area = 261 + 9 = 270 cm²; divide by AD to get AB."
   ],
   "source": "Nan Hua 2025 P4 End-of-Year Exam Q46",
   "image_needed": true,
   "image_options": false,
   "image_file": "q46.png",
   "image_page": 22,
   "image_bbox": [
    0.16,
    0.18,
    0.82,
    0.3
   ],
   "image_loc": "Figure 1 (rectangle ABCD with AB marked '?') and Figure 2 (rectangle with square WXCY cut from corner C), below the question",
   "notes": "Answer key: 45 cm."
  }
 ]
}