Laminate and cut out each of these cards.
This activity is aligned with MAFS.5.OA.1.2 (Write and interpret numerical expressions).
There are various ways to use these cards in your classroom. My personal favorites are 1) to use the cards for a matching game where the students match the word problem to the numerical expression and 2) separate the word problems from the expressions and have students create word problems for the expressions and find the expressions for the word problems.
Each word problem is printed next to its correlated expression, which can be used as your answer key.