



 
Hi Audrey, You can certainly use algebra to solve this problem. Suppose the digits are m and n so the number is 10m + n. You know two facts The sum of the digits is 9
If the digits are reversed, the new number if 63 greater than the original number.
Solve these two equations for m and n. There is however an easier and more insightful way to solve the problem. It involves knowing one fact.
The sum of the digits of the twodigit number you started with is 9 which is divisible by 9. Hence the twodigit number is divisible by 9. What are the twodigit numbers which are divisible by 9?
Add 63 to each of these. Which one results in a twodigit number with the digits reversed? Penny  


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