There are 50 multiples of 8 between 100 - 500
I know you are the same guy from like the problem two minutes ago so utilize these three steps.
1. Find first multiple of 8 in 100-500 = 104
Now there are 396 numbers from 104-500
2. Find how many multiples of 8 are in 396 = 49
3. Add 1 (first multiple) = 49+1