Nathan B. answered 08/22/18
Tutor
5
(20)
Elementary and Algebraic skilled
We start off with a two-digit number. This means we start off thus knowing that it must range from 10-99. One less would be 9, a single digit; one more would be 100, a three-digit.
Zero is not a digit, so we know it cannot be 10, 20, 30, 40 etc.
Let's put 1 in the ones position. That gives us _1 so far. We know that the tens position is 8 more than the ones, so we add:
1 + 8 = 9
That gives us the number 91.
Ask yourself this: what would happen if you had a 2 in the ones position? If you added 8 to 2, would you have a two-digit number, or would it kick up to three?