Question

Helpppp

Answer 1

This is something called compatible numbers.  By doing this, you are applying the distributive property, but you are also making the problem simple enough to do in your head.  You gave 8 x 45.....Leave the 8 alone, but take the 45 and split it into two numbers that would add up to 45.  Don't go too wild and crazy, but keep it simple like 40 and 5.  Now multiply each number by 8......8 x 40 + 8 x 5.....you come up with 320 + 40......when you add the two together, you have a sum of 360.  Clear as mud?

Answer 2

Mentally, I'd find it out like this:

8(40+5)

=8*40+8*5

=8*4*10+8*5

=320+40

=360