I have given it more thought; but I have not been able to come up with the form you want. Is the 2nd one OK with only 3 threes? Is there a textbook involved with these puzzels?

I'm sorry too. I just don't see how to do it if you aren't allowed to repeat the operations.

I've got one that works for 4, but I for 2 and 7 I have only come up with the same ones nasacort has... the ones that repeat operations.

Here's one for 4:

3^(3-3) + 3 = 3^0 + 3 = 1 + 3 = 4

I will keep thinking about it and you can keep this question open for twenty-four hours. If you still don't have an answer you are satisfied with at that point, you can either let the question close without accepting any answers or you can re-list it.