I need help asap

Question

There are 5 white marbles, 4 green marbles, and 3 yellow marbles in a bag.

a) How many ways can you select at least 1 marble (colour doesn’t matter)?

b) How many ways can you select exactly one of each colour?

Answer 1

12C12 + 12C11 + 12C10 + 12C9 + ... 12Cn ..+ 12C3 + 12C2 + 12C1

= 1 + 12 + 66 + 220 + 495 + 792 + 792 + 495 +220 + 66 + 12 + 1

= 3172

unless order matters

then

12P12 + 12P11 + ... + 12Pn + ... 12P2 + 12P1

= 1 + ...