That's 11 things taken 3 at a time. The combinations of 11 things taken 3 at a time is C(11,3) == 165 You can also get that on a TI-84 Press ON Press CLEAR Press 1 Press 1 Press MATH Press the left arrow key Press 3 Press 3 Press ENTER You'll see this: 11 nCr 3 165 Edwin