Question

two-digit natural numbers are formed, with replacement, from 0 through 9. how many two-digit odd numbers are possible?

Answer 1

Let's solve this step by step:

1. The first digit has 9 choices --> 1 through 9
2. The second digit has 10 choices --> 0 through 9

  *the first digit cannot have '0' as its first digit since it would make the

  number one-digit

Total Choice: 9 choices * 10 choices = 90 choices

Hope that helps!