2-Digit x 2-Digit Long Multiplication

What is long multiplication?

  • Long multiplication is for multiplying two 2-digit numbers.
  • We do two separate multiplications and add them together.
  • First, multiply by the ones digit.
  • Then, multiply by the tens digit (put a zero placeholder first).
  • Finally, add both rows to get the answer.

Example: 24 x 13

  1. Write 24 on top and 13 below.
  2. Row 1: Multiply 24 by 3 (the ones digit of 13).
  3. 3 x 4 = 12. Write 2, carry 1. Then 3 x 2 = 6, plus 1 = 7.
  4. Row 1 = 72.
  5. Row 2: Multiply 24 by 10 (the tens digit of 13). Write a 0 first.
  6. 1 x 4 = 4. Write 4. Then 1 x 2 = 2. Write 2. Row 2 = 240.
  7. Add: 72 + 240 = 312.
  8. Answer: 24 x 13 = 312.

Let us try: 32 x 21

  • Row 1: Multiply 32 by 1 (ones digit of 21).
  • 1 x 2 = 2. 1 x 3 = 3. Row 1 = 32.
  • Row 2: Multiply 32 by 20. Write a 0 first.
  • 2 x 2 = 4. 2 x 3 = 6. Row 2 = 640.
  • Add: 32 + 640 = 672.
  • Answer: 32 x 21 = 672.

Now try these yourself

  • 15 x 12 = ? (Row 1: 15 x 2 = 30. Row 2: 15 x 10 = 150. Add them.)
  • 23 x 14 = ? (Row 1: 23 x 4. Row 2: 23 x 10. Add them.)
  • 34 x 22 = ? (Row 1: 34 x 2. Row 2: 34 x 20. Add them.)
  • Remember: ones row first, then tens row with a zero placeholder.
Start the interactive 2-Digit x 2-Digit Long Multiplication lesson →