# Math Help - Find the number of integers

1. ## Find the number of integers

Find the number of integers from 1 to 10,000 which are divisible by either 13 or 51
regards
Sridhar

2. Hello yshridhar

Welcome to Math Help Forum!
Originally Posted by yshridhar
Find the number of integers from 1 to 10,000 which are divisible by either 13 or 51
regards
Sridhar
$10,000\div13 = 769.1$, so there are $769$ integers from $1$ to $10,000$ that are divisible by $13$.

In the same way, you can find the number of integers that are divisible by $51$.

Add this number to $769$. Then you will need to subtract the number of integers that are divisible by $13\times51\; (= 663)$, because they will have been counted twice. (Note that $51 = 3 \times 17$, so $51$ and $13$ have no common factors.)

Can you complete this now?