[
  "Draw a bar model: find the remaining cake after keeping some for the party, then divide that remainder equally among 6 children.",
  "Remaining after keeping 2/5 = 1 - 2/5 = 3/5. Each child gets 3/5 / 6 = 3/5 x 1/6 = 3/30 = 1/10.",
  "Each child got 1/10 of the cake. Answer: 1/10 (option D)."
]