How many possible combinations of 4 numbers 1-9?

1.       There are 10, 000 combinations, you have 10 choices for the four digit and there are 10 x 10 x 10 x 10 which is 4-digit combination from 1-9. This is called combinations; the calculation comes out to 10^4. 

step-by-step explanation:

try remembering the steps

the answer is c

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