"Mixed Skills Math Word Problems: Fractions, Money, and More" is a fantastic worksheet for skills review, critical thinking practice, or as an early finisher because it contains a wide variety of math problems.
Each worksheet has two word problems contained within boxes with plenty of room for students to show their work and find the answer. They encourage complex thinking with questions like "The sum of two counting numbers is 51. One number is three larger than the other. What are the two numbers?" Other questions encourage number sense by asking students to make larger and smaller numbers using a series of digits, while still others encourage rounding, counting coins, and more.
Math word problems are a great way to encourage critical thinking and problem-solving skills because they don't just require students to find an answer to a numerical problem. They require students to understand the context and decode the problem from what they read in addition to finding the solution.
When choosing math word problems, make sure you choose problems that are grade-level appropriate and reflect skills students have already learned if you want them to complete the problems by themselves. Harder problems can be solved by pairs of students or completed as a class to stretch student thinking.