Mental Arithmetic: multiplication facts by adding partial products mentally

Mental Arithmetic

Complete multiplication facts by adding partial products mentally.

Now we break the following numbers, for example, 53 = 50 + 3, 98 = 90 + 8.

In 53, why should numbers to be parted into 50+3, because nearest multiples of 10 to 53 is 50 and add the remaining number 3 with it.

EXAMPLE 1

Complete the following multiplication facts by adding partial products.

6 x 45 = 6 x (40+5)

= 6 x 40 + 6 x 5

Break 45 into two parts 40 + 5

Then multiply those two parts separately as:

6 x 40 = 240

6 x 5 = 30

Then add these two partial results.

6 x 45 = 270