1st GradeMathOperations and Algebraic Thinking
1.OA.8
Determine the unknown whole number in an addition or subtraction equation relating three whole numbers.
12 Free Worksheets for 1.OA.8
All worksheets below are aligned to CCSS 1.OA.8 and printable as PDF.
Related 1st Grade Standards (Operations and Algebraic Thinking)
1.OA.1Use addition and subtraction within 20 to solve word problems involving situations of adding to, taking from, putting together, taking apart, and comparing.1.OA.3Apply properties of operations as strategies to add and subtract.1.OA.5Relate counting to addition and subtraction (e.g., by counting on 2 to add 2).1.OA.A.1Use addition and subtraction within 20 to solve word problems involving situations of adding to, taking from, putting together, taking apart, and comparing, with unknowns in all positions.1.OA.B.4Understand subtraction as an unknown-addend problem.1.OA.C.6Add and subtract within 20, demonstrating fluency for addition and subtraction within 10. Use strategies such as counting on; making ten; decomposing a number leading to a ten; using the relationship between addition and subtraction; and creating equivalent but easier or known sums.