Basic holdem combination question.

[t_rex]

OK. For your hole cards in holdem, there are 169 distinct combinations. I don't understand how this number is mathematically calculated though.

I get that there are 13 pairs, and 78 suited cards (2 card combinations out of 13 cards - suit is irrelevant, so no need to multipy by 4). What I don't really understand is how the 78 unsuited combinations are calculated. Could someone explain this to me?

Thanks