Give your students practice with solving addition and subtraction word problems within 20 using this set of 15 practice sheets! The practice sheets give you a quick and easy framework for teaching and reinforcing this Common Core concept (1.OA.1 and 1.OA.2). The pack starts with 5 pages of addition word problems, including result unknown, start unknown, and change unknown prompts, as called for under the Common Core standards (appendix). Following those pages are 5 pages of subtraction probl