Spoiler:
I cant remember how to do it but i know its possible.
using only the numbers 6, 7, 8, 9, 10.
using only the operations +, -, /, *
you have to make 12
in addition you are only alowed to use them once and you have to use all of them
parentheses are alowed, but powers are not.
Hmm. Is the problem statement this:
1. "Using all of the following symbols exactly once, 6, 7, 8, ,9, 10 and +, -, *, /, try and make the number 12." or is it
2. "Using any of the following symbols at most once, 6, 7, 8, ,9, 10 and +, -, *, /, try and make the number 12."?
The OP wasn't worded clearly there, in my opinion.