Q1. There are 7 digits. Pretend they are all different, a,b,c,d,e,f,g say.

Find all the possibilities:

a, ab, abc, .......fg, g

Now allow for the repeats by dividing (eg if all 4s then divide by 4!)

Might be easier to count by taking all the 4s; then only three 4s then only two etc.

Q2. No number can be over 10 or under 1.

So 10 + 1 + 1

9 + 2 + 1

9 + 1 + 2

etc. It's not so bad to continue like this, is it?

That should show you a generating technique which will make Q3 easy.

Bob