MathKits - Multiplication

1. Multiplying Two Numbers

Let's go through the steps to multiply two numbers.

Step 1: Write the numbers vertically, one under the other.

Example: Multiply 23 × 45

Step 1:

                23
              × 45

Step 2: Multiply the ones column. 5 × 3 = 15. Write 5, carry over 1.

Example: 5 × 3 = 15, write 5, carry 1.

                Carry: 1
                23
              × 45
            -----------
                115

Step 3: Now multiply 5 × 2 = 10, plus the carry over 1 gives 11. Write 11.

Example: 5 × 2 = 10, plus carry 1 = 11.

                23
              × 45
            -----------
               115

Step 4: Now multiply the tens column. 4 × 3 = 12. Write 2, carry over 1.

Example: 4 × 3 = 12, write 2, carry 1.

                Carry: 1
                23
              × 45
            -----------
              115
            +920

Step 5: Finally, multiply 4 × 2 = 8, plus the carry over 1 makes 9. Write 9.

Example: 4 × 2 = 8, plus carry 1 = 9.

                23
              × 45
            -----------
              115
            +920
            -----------
              1035