Addition and subtraction within 20 is a second grade math single-digit addition and subtraction unit focused on making ten, adding ten, and using ten to add and subtract. This unit specifically focuses on establishing 10 as a benchmark number to give students strategies and practice in developing automaticity with larger math facts before moving onto multi-digit addition and subtraction.
In the base-10 number system, understanding how to use 10 as a benchmark number is key for students to obtain fluency and automaticity with their math facts, be able to add and subtract two-digit numbers in their heads, and use place value and compensation strategies with larger numbers. If students can learn how to use 10 to add an subtract smaller numbers within 20, they will have so many tools and strategies at their disposal when adding and subtracting multi-digit numbers.
Included in the unit are four different sections specifically focused on making ten, adding ten, using ten to add and using ten to subtract. Each section has:
• Worksheets / No-Prep Printables (with ten frames, number bonds, and number lines)
• Cut and Paste Worksheets
• Partner Matching Cards (with ten frames, numbers bonds, and bar models)
• Quick Checks in three different formats
There are enough resources in this unit to provide you with materials for whole group direct instruction as well as small group Response to Intervention (RtI) follow-up. You can revisit these concepts all year long as students either need a refresher on the power of using 10 as a benchmark number or are now ready to understand how to use the number 10 to solve math facts.