operations · Year 5 · AC9M5N06
Long multiplication
To multiply two 2-digit numbers, split the second into tens and units and multiply each part. For 23 × 14: 23 × 4 = 92, and 23 × 10 = 230. Add the partial products: 92 + 230 = 322. The tens row is a multiple of ten, so it always ends in zero — never forget that shift.
Sample questions
21 × 12 = ?
- Split 12 into 10 + 2.
- 21 × 2 = 42.
- 21 × 10 = 210 (remember the second row is a multiple of ten).
- 42 + 210 = 252.
Answer: 252
24 × 15 = ?
- Split 15 into 10 + 5.
- 24 × 5 = 120.
- 24 × 10 = 240 (remember the second row is a multiple of ten).
- 120 + 240 = 360.
Answer: 360
37 × 18 = ?
- Split 18 into 10 + 8.
- 37 × 8 = 296.
- 37 × 10 = 370 (remember the second row is a multiple of ten).
- 296 + 370 = 666.
Answer: 666