Solution

36639

First name
Harriet
School
BGS
Country
Age
10

14 = 9 + 5
13 = 6 + 7
8 = 0 + 8
7 = 3 + 4
3 = 1 + 2

I started with the numbers that had the least ways of making them and I knew which numbers I had to use first. I then used elimination.