Question

How many integers between 10 and 500 begin and end in 3?

Answer 1

If from 0 - 10 there is 1 number ending in 3 (3) we'll aplly the same logic to 500.

Between 0-10 there is 3. Between 10 - 20 there is 13. Between 20-30 there is 23. Between 30-40 there is 33, etc.

If we divide 500 into 10 we get 50:

500 / 10 = 50

That means there are 50 groups of 10 in the number 500. If we know that every 10 numbers has 1 ending in 3, we multiply 1 by 50:

1 x 50 = 50

So, our conclusion is, that there are 50 numbers ending in 3 between 10 and 500.

Hope it helped,

BioTeacher101