Like 1235 or 8067?
If you allow leading zeros, then 10 000.
If you disallow leading zeros, then 9 000.
* * * * *
Those are the numbers of PERMUTATIONS, not COMBINATIONS.
In combinations the order does not matter, so 1234 = 4312 = 2314 etc.
The number of combinations is (10*9*8*7)/(4*3*2*1) = 210.
The question of leading 0s does not arise because there is no order to the set of numbers in the combination so there is no "leading".
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How many four digit combinations can be made from the number nine? Example, 1+1+2+5=9.
To calculate the number of 3-digit combinations that can be made from the numbers 1-9, we can use the formula for permutations. Since repetition is allowed, we use the formula for permutations with repetition, which is n^r, where n is the total number of options (10 in this case) and r is the number of digits in each combination (3 in this case). Therefore, the total number of 3-digit combinations that can be made from the numbers 1-9 is 10^3 = 1000.
All the numbers from 0 to 999 so 1000 numbers However if you mean only using each number once the answer is about 720 * * * * * No. The above answer refers to the number of permutations. Permutations are NOT the same as combinations as anyone who has studies any probability theory can tell you. The number of combinations is 9C3 = 9*8*7/3*2*1 = 84
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