The difference of 10 and a number is negative eight, what's the number?

The answer is 18, because 10-18 is - 8.

Try this on a piece of paper or something to get the same answer

18

Step-by-step explanation:

Difference means to subtract. Simply subtracting 18 from 10 gets you negative 8. To find this out you could also reverse this process by adding 8 to - 8 and getting 0, then adding 10 to find out you ADD 18 to get 10. So subtracting 18 gets you - 8!