SOLUTION: how many integers between 9 and 99 have an even tens digit and an odd units (ones) digit?

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Question 954263: how many integers between 9 and 99 have an even tens digit and an odd units (ones) digit?
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

First, which numbers between 9 and 99 have an even+tens digit?
All the 20s, 40s, 60s, and 80s.
Now just look at the 20s. How many of those have odd units (ones) digits?
That would be 21, 23, 25,+27, and 29, which makes five numbers.
It is the same for the 40s, 60s, and 80s, so the final answer is:
5%2A4+=+20
there is 20 integers between 9 and 99 that have an even tens digit and an odd units (ones) digit