[
  "When the tenths in the first number are too small to subtract, regroup 1 one as 10 tenths.",
  "7.2 = 6 ones + 12 tenths. 2.5 = 2 ones + 5 tenths. Ones: 6 - 2 = 4. Tenths: 12 - 5 = ?",
  "7.2 - 2.5 = 4.7. Answer: 4.7."
]