The sum of two consecutive integers is 68, what is the smaller number?
Two consecutive number means that one of them is even and the other odd. Consequently their sum will be odd.
For the sum to be 68 the question has to be one of:
Two consecutive even numbers give an even number answer.
Two consecutive odd numbers give an even number answer.
Subtract 2 from both sides
Thus the 1st even number is
Thus the next even number is
Using the notation from the first solution
The second odd number will be
Divide both sides by 4
So the first odd number is
So the second odd number is