# Operations and Algebraic Thinking (OA)

• 1.OA.A  Represent and solve problems involving addition and subtraction.
• 1.OA.A.1  Use addition and subtraction within 20 to solve word problems with unknowns in all positions (e.g., by using objects, drawings, and/or equations with a symbol for the unknown number to represent the problem).  See Table 1.
• 1.OA.A.2  Solve word problems that call for addition of three whole numbers whose sum is less than or equal to 20 (e.g., by using objects, drawings, and/or equations with a symbol for the unknown number to represent the problem). See Table 1.
• 1.OA.B  Understand and apply properties of operations and the relationship between addition and subtraction.
• 1.OA.B.3  Apply properties of operations (commutative and associative properties of addition) as strategies to add and subtract within 20. (Students need not use formal terms for these properties.)
• 1.OA.B.4  Understand subtraction as an unknown-addend problem within 20 (e.g., subtract 10 - 8 by finding the number that makes 10 when added to 8).
• 1.OA.C  Add and subtract within 10.
• 1.OA.C.5  Relate counting to addition and subtraction (e.g., by using counting on 2 to add 2).
• 1.OA.C.6  Fluently add and subtract within 10.
• 1.OA.D  Work with addition and subtraction equations.
• 1.OA.D.7  Understand the meaning of the equal sign, and determine if equations involving addition and subtraction are true or false (e.g., Which of the following equations are true and which are false? 6 + 1 = 6 - 1, 7 = 8 - 1, 5 + 2 = 2 + 5, 4 + 1 = 5 + 2).
• 1.OA.D.8  Determine the unknown whole number in an addition or subtraction equation relating three whole numbers (e.g., determine the unknown number that makes the equation true in each of the equations 8 + o = 11, 5 = o - 3, 6 + 6 = o).

*Please note that students at CTA Independence are accelerated in math therefore are learning the level one year above their current grade.