Hello from MrBillDoesMath!
Answer:
10^7 choices
Discussion:
The first digit can be any of 10 choices : (0,1,2,3,4,5,6,7,8,9)
The second digit can also be any of the same 10 choices as numbers can be repeated.
So for a seven digit number there are a total of
10 * 10 * 10 * 10 * 10 * 10 * 10 ( 7 times)
= 10^7 numbers
Thank you,
MrB
