#1**-2 **

The largest multiple of 7 is 7*14

Thus 14 multiples

Largest of 11 is 11*9, 9 multiples

One is 7*11 = 77, and so 14+9-1 = 22

If you don't understand anything feel free to ask

hugomimihu Jun 22, 2020

#2**+3 **

A quick summary of what hugomimihu wrote:

First find all of 7's multiples between 1-100.

Then find all of 11's multiples between 1-100.

Add the sums together.

Minus the numbers that repeat (basically find the least common multiple of 7 and 11 which is 77-- Since there is only one multiple of 77 between 1-100, you only need to minus one.)

amazingxin777 Jun 22, 2020