I am looking for a formula to subtract cells if certain criteria match. See
example below.


Data that is given
A B C
1 123 4
2 123 7
3 124 8
4 124 12
5 125 10
6 125 20
7

Data in C with formula
A B C
1 123 4
2 123 7 3
3 124 8
4 124 12 4
5 125 10
6 125 20 10
7