Consecutive Numbers

"Two consecutive whole numbers add up to 25. What are they?" Consecutive means one after the other. If the first number is $n$, the next one is $n+1$. Their sum is 25:

$$n+n+1 = 25$$

Collect the like terms to get $2n+1 = 25$. Subtract 1 from both sides, then divide by 2, and you get $n = 12$. The numbers are 12 and 13. Check that $12+13 = 25$.

Consecutive even numbers differ by 2, and so do consecutive odd numbers. Write them as $n$ and $n+2$. Write every quantity in the problem in terms of the same unknown. Then use the relationship the problem gives to write one equation.