Assuming you are using the standard English alphabet, the number of combinations you can make are: 26 x 26 = 676 combinations.
4*3*2*1 = 24 different combinations.
How many four digit combinations can be made from the number nine? Example, 1+1+2+5=9.
90
The answer is 10C3 = 10*9*8/(3*2*1) = 120 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.
Their is 25 combinations
Two make combinations you would take 2x1=2 combinations only
Assuming the digits cannot be repeated, there are 7 combinations with 1 digit, 21 combinations with 2 digits, 35 combinations with 3 digits, 35 combinations with 4 digits, 21 combinations with 5 digits, 7 combinations with 6 digits and 1 combinations with 7 digits. That makes a total of 2^7 - 1 = 127: too many for me to list. If digits can be repeated, there are infinitely many combinations.
14*13/(2*1) = 91 combintions.
There are 8*7/(2*1) = 28 combinations.
There are 9C2 = 9*8/(2*1) = 36 2-digit combinations.
There are 11C2 = 11*10/(2*1) = 55 combinations.
There are 56C5 = 56*55*54*53*51/(5*4*3*2*1) = 3,819,816 combinations.
There are 43 combinations of various quantities of quarters (0, 1 or 2), dimes (0 to 5), nickels (0 to 10) and pennies (2 to 52) that make 52 cents.
14 * * * * * Wrong! There are 15. 4 combinations of 1 number, 6 combinations of 2 number, 4 combinations of 3 numbers, and 1 combination of 4 numbers.
Combinations from 90 objects, taken 3 at a time is 90C3 = 90*89*88/(3*2*1) = 117,480.