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.

Complete the following multiplication facts by adding partial products.

$$ 6 \times 45 = 6 \times (40+5) $$

$$ = 6 \times 40 + 6 \times 5 $$

Break 45 into two parts $40 + 5$

Then multiply those two parts separately as:

$$ 6 \times 40 = 240 $$

$$ 6 \times 5 = 30 $$

Then add these two partial results.

$$ 6 \times 45 = 270 $$