[
  "When subtracting a decimal from a whole number, regroup 1 whole as 10 tenths first.",
  "3 = 2 ones + 10 tenths. 0.7 = 0 ones + 7 tenths. Ones: 2 - 0 = 2. Tenths: 10 - 7 = ?",
  "3 - 0.7 = 2.3. Answer: 2.3."
]