A number with a zero in the ones place is a **multiple of ten**.

A number multiplied by a multiple of ten can be thought of as a **multiplication fact times ten**.

40 is a multiple of 10, because 4 × 10 = 40. So, think of 40 as 4 tens.

Since 40 is 4 tens, 3 × 40 is 3 groups of 4 tens.

This is the same as 12 tens.

12 tens is the same as 120. So, 3 × 40 = 120.