1.OA.D.8 Worksheets: Find the Missing Number
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1.OA.D.8 (Operations and Algebraic Thinking): Find the unknown number in an addition or subtraction equation.
About this standard
In first grade the unknown can be in any position, as in 8 + ? = 11 or ? - 3 = 5, and the start-unknown kind is the hardest. Turning a subtraction blank into "what plus this makes that?" is the move that unlocks most of these. Begin with Missing Addends Within 10, then go to Missing Numbers in Subtraction Within 20, and see the equal sign itself in True or False Equations.
Worksheets for 1.OA.D.8
Missing Addends Within 10
Missing Addends With Three Numbers
Missing Addends Within 20
Missing Numbers in Subtraction Within 20
Balancing Equations Within 20