It depends on the sizes of the combinations. For example, there is only one combination of 7 things out of 7, but there are 21 combinations of two items.
12 how come
12
There are 24C12 = 24!/[12!*12!] = 2,704,156 combinations.
12 Combinations.
26 = 64 combinations, including the null combination - which contains no numbers.
There are 24C12 = 24*23*...*13/(12*11*...*1) = 2,704,156 combinations.
32 combinations. 4 of these will have no toppings, or all three toppings, 12 will have one topping and another 12 will have 2 toppings.
144 a gross = 12 dozen 12x12=144
Only three: 12, 13 and 23. Remember that the combinations 12 and 21 are the same.
30
6 or 12
There are 29 ways.