Question

Mental math 5×395=5×(_ - _)step by step how do you solve this problem?

Answer 1

You want to use the distributive property, i.e. the possibility to distribute a multiplication to both terms of an sum/subtraction.

In this case, if you think of 395 as of 400-5, you have

$5 \times 395 = 5 \times (400-5)$

And you can use the distributive property to write

$5 \times (400-5) = 5\times 400 - 5\times 5$

Both of these multiplications are easy to perform in your mind:

$5\times 400 - 5\times 5 = 2000 - 25 = 1975$