Not quite. You can read about permutations on
Wikipedia; I haven't found their combinations page but I am sure it will be there.
The formula for
nC
r, whch is what it was called when I was at School (we still had steam trains on main lines in those days
) is
n! ÷ ((
n −
r)! × r!). For ₆C₄ that comes to 6 × 5 × 4 × 3 × 2[ × 1] ÷ ((4 × 3 × 2[ × 1]) × (2[ × 1])), which reduces to 15.
That means there are 15 different ways to draw 4 our of 6, as long as you don't care about the order of drawing: 1234 1235 1236 1245 1246 1256 1345 1346 1356 1456 2345 2346 2356 2456 3456, and there are also fifteen ways to draw two out of six which are the same as the ways of leaving two behind (i.e. the complement of the above fifteen sets): 56 46 45 36 35 34 26 25 24 23 16 15 14 13 12.