The tens digit of a certain number is five more than the units digit. The sum of the digit is 9. Find the number
Let the units digit be x and the tens digit be x + 5.
Given that the sum of the digits is 9:
x + (x + 5) = 9
2x + 5 = 9
2x = 4
x = 2
Therefore, the units digit is 2 and the tens digit is 2 + 5 = 7.
So, the number is 72.