[
  "Draw a bar model: flour = 5 units, butter = 1 unit. The difference of 4 units equals 30 g, the extra flour.",
  "1 unit = 30 / 4 = 7.5 g. Flour is 5 units: 5 x 7.5 = 37.5 g. Round to the nearest whole number.",
  "He used 38 g of flour."
]