The only digit that can be in the ones place of a number that has 5 as a factor is 0 or 5.
When we say a number has 5 as a factor, it means that the number is divisible by 5 without any remainder. The numbers that meet this criterion end with either a 0 or a 5. For example:
- 10 (ends with 0)
- 15 (ends with 5)
- 20 (ends with 0)
- 25 (ends with 5)
So, for any whole number to have 5 as a factor, its last digit must be one of these two possibilities.