Question

Find the number of 3 digits numbers divisible by 3 or 5

Answer 1

The numbler of 3 digit number of divisible by 3 or 5
(Number divisible by 3) + (Number divisible by 5)
A number is divisible by 5 if and only if it’s last digit is either a 0 or a 5.
$9\times 10\times 2=180$
Similarly, find the number divisible by 3 and 15.