Question 1199873
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If a formal algebraic solution is not required, you can use a shortcut to solve the problem.<br>
When a 2-digit number has its digits reversed and the two numbers are compared, the difference is 9 times the difference between the digits.<br>
In this problem, the difference between the two numbers is 45, so the difference between the two digits is 5.<br>
Now we know the sum of the digits is 11 and their difference is 5; quick reasoning and mental arithmetic tells us the two digits are 8 and 3.<br>
Then, since the original number is greater, it is 83.<br>
ANSWER: 83<br>
It is easy to prove algebraically that the difference of the two numbers is 9 times the difference of the digits.<br>
Let the original number have tens digit a and units digit b; the value of the number is 10a+b.<br>
The number with the digits reversed has the value 10b+a.<br>
The difference between the two numbers is<br>
(10a+b)-(10b+a) = 9a-9b = 9(a-b)<br>