There are 8*7/(2*1) = 28 combinations.
There are 11C2 = 11*10/(2*1) = 55 combinations.
There are 21 combinations.
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There are 9C2 = 9*8/(2*1) = 36 2-digit combinations.
You can make 5 combinations of 1 number, 10 combinations of 2 numbers, 10 combinations of 3 numbers, 5 combinations of 4 numbers, and 1 combinations of 5 number. 31 in all.
There are 8*7/(2*1) = 28 combinations.
Only three: 12, 13 and 23. Remember that the combinations 12 and 21 are the same.
There are 11C2 = 11*10/(2*1) = 55 combinations.
To calculate the number of 4-digit combinations you can get from the numbers 1, 2, 2, and 6, we need to consider that the number 2 is repeated. Therefore, the total number of combinations is calculated using the formula for permutations of a multiset, which is 4! / (2!1!1!) = 12. So, there are 12 unique 4-digit combinations that can be formed from the numbers 1, 2, 2, and 6.
There are 21 combinations.
none
There are 32C3 = 32*31*30/(3*2*1) = 4960 combinations. I do not have the inclination to list them all.
10 * * * * * That is just plain wrong! It depends on how many numbers in each combination but there are 1 combination of 4 numbers out of 4, 4 combinations of 3 numbers out of 4, 6 combinations of 2 numbers out of 4, 4 combinations of 1 number out of 4. A grand total of 15 (= 24-1) combinations.
There are 45 combinations.
There are 233 - 1 = 8,589,934,591 combinations, not including the null combination.
There are 9C2 = 9*8/(2*1) = 36 2-digit combinations.