Algebra 2 help, permutation combination

How many 7 digit phone numbers are available if all digits (0 through 9) can be repeated BUT no phone number can start with 0?

i think its a combination i cant remember

It's actually easier than that: you have 9 choices for the first number (since you can't use 0) and 10 for each of the other digits. so 9 X 10^6, or 9,000,000.

From the left if you go on writing the numbers, the number of possibilities is
9x10^6 = 9000000

in the first place its 9c1*10*10*10*10*10*10
9*1000000=9000000

9 x 10 x 10 x 10 x 10 x 10 x 10 = 9,000,000

:)>