If the division of a natural number n by 5 leaves a remainder of 3, what might be the ones digit of n?

Explanation

If `N/5` gives remainder `3`, then `N=5a+3` for a natural number `a`.
For a being even, `5a` has a unit place `0` and `3` added gives unit place `3`.
For a being odd, 5a has unit place `5` and `3` added gives unit place `8`.
So, it is either `3` or `8`.