Find the common difference. From 820 to 780 is 40 over 2 steps.
• Common difference = 40 ÷ 2 = 20, decreasing
• The pattern decreases by 20 each step.
• First blank: 820 − 20 = 800
• Second blank: 780 − 20 = 760
• Check: 760 − 20 = 740 ✓ ; 740 − 20 = 720 ✓
Final Answer: 800, 760