From 1 to 100, there are 34 numbers divisible by 5 and 7 Is a number that can be divided by 5 or 7

From 1 to 100, there are 34 numbers divisible by 5 and 7 Is a number that can be divided by 5 or 7

There are 20 numbers divisible by 5, 14 by 7 and 2 by 35
So, there are 20 + 14 - 2 = 32 numbers divisible by 5 or 7
Note that it's better to use "or" instead of "and" here. You get 34 because 35 and 70 are calculated one more time

The number divisible by () () at the same time must be divisible by 36. The number divisible by () () and () at the same time must be divisible by 30
Abcab stands for a six digit number. Abcabc must be divisible by () and (). Abcdabcd must be divisible by () and ()

The number that can be divisible by (4) (9) at the same time must be divisible by 36, and the number that can be divisible by (2) (3) and (5) at the same time must be divisible by 30
Abcab stands for a 6-digit number. Abcabc must be divisible by (7) and (13). Abcdabcd must be divisible by (73) and (137)

The sum of numbers from 1 to 100 divisible by 2 and 3 at the same time

816