Understand subtraction as an unknown-addend problem. For example, subtract 10 – 8 by finding the number that makes 10 when added to 8.

Lesson Planning and Activity Resources

Math Playground.JPG
1.OA--Interactive games for Operations and Algebraic Thinking

Grade 1 Unit: Operations & Algebraic Thinking
(from Georgia Department of Education)
This unit addresses KCAS 1.OA.1-8 and 1.MD.4.
common core sheets.JPGhttp://www.commoncoresheets.com/SortedByGrade.php?Sorted=1oa4
Each sheet has 20 problems relating subtraction to addition.