Is it 36?

We want to show that there are 42 different four-digit numbers Anna can form. 1) Let the numbers Anna can form be of the form abcd. First, we have that a>6, because the smallest value of the sum b+c+d is 6. So, what we have to do is just check how many numbers exist (where a>b+c+d) for: a) b,c,d=1,2,3 b) b,c,d=1,2,4 c) b,c,d=1,2,5 d) b,c,d= 2,3,4 After that, we find that the answer is 42.