- A9
- B10
- C8
- D18
Step-by-Step Solution
They are 18, 27, 36, 45, 54, 63, 72, 81 and 90: nine numbers (the tens digit runs from 1 to 9, and 09 is not two-digit).
Answer: A) 9
How many two-digit numbers have digits that add up to 9?
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