When multiplying the number 5 by an even number, there is a quick way to find the answer.
For example, 5 x 4 =
- Step 1: Take the number being multiplied by 5 and cut it in half, this makes the number 4 become the number 2.
- Step 2: Add a zero to the number to find the answer. In this case, the answer is 20.
5 x 4 = 20
When multiplying an odd number times 5, the formula is a bit different.
For instance, consider 5 x 3.
- Step 1: Subtract one from the number being multiplied by 5, in this instance the number 3 becomes the number 2.
- Step 2: Now halve the number 2, which makes it the number 1. Make 5 the last digit. The number produced is 15, which is the answer.
5 x 3 = 15