The sum of the two digits of a number is 16. The number formed by reversing the digits is 18 more than the original number. Find the original number and its reversal

Answer: 97 and 79

Why:

Every number has a ones place digit, tens place digit, hundreds place digit, so on and so forth.

We are looking at a 2 digit number so let's say that the tens place digit is "a" and the ones place digit is "b".

Now I'm going to write out what we know using these variables.

a + b = 16

And 10*a + b = 10b + a + 18

Now you have two unknowns and two equations and you just solve for a or b. Then plug in a to get b in a+b = 16. Or viceversa.