Elimination adds or subtracts two equations so that one letter disappears. These free printable worksheets give pairs where that works cleanly, with whole-number answers for both letters.
If they get stuck
The answer key prints on a separate page.
If one equation has +9y and the other has −9y, adding them leaves an equation in x alone. That is the whole idea, and the skill is spotting which operation makes the cancellation happen — add when the signs differ, subtract when they match. Getting that backwards doubles the term instead of removing it, which is visible immediately.
The half that gets forgotten is the second letter. Finding x = 3 is not the answer; putting 3 back into either original equation and finding y is. A solution to a pair of equations is a pair of numbers, and an answer with one number in it is half done however correct that number is.
One question from a sheet like this one, worked a step at a time — with a sentence saying what just happened and why.
Systems by elimination, step by step