A phone number contains 7 digits. How many different numbers can be made using the digits 0–9 if the first digit is not 0 and none of the digits can be repeated?

a. 362,880
b. 3,780
c. 24

Question

A phone number contains 7 digits. How many different numbers can be made using the digits 0–9 if the first digit is not 0 and none of the digits can be repeated?

a. 362,880
b. 3,780
c. 24

anonymous · Answer

beautiful combinations and permutations question

anonymous · Answer

how does that work it's not one of my answers?

anonymous · Answer

if the first digit is not zero, then that leaves 9 possible numbers

anonymous · Answer

how do i calculate this?

anonymous · Answer

therefore:

anonymous · Answer

9 in the first combination

anonymous · Answer

correctly permutation

anonymous · Answer

|dw:1432926939710:dw|
giving 362, 880 posssibilities