Subtraction: Unknown Addend Problems1st Grade • Half Day Lesson Plan
Subject: Math, Operations and Algebraic Thinking
Type: Half Day Lesson Plan
Skills: Addition Commutative Property, Subtraction as Unknown Addends
File Type: PDF Document
Materials Needed: blank paper, pencils, crayons/colored pencils, counting manipulatives (10 per student), decks of cards (1 deck per small group) -or- use optional printable number cards, and a document camera or whiteboard
Printable Resources: Printable Resources: “Exit Slips” (as an optional assessment component, 1 copy per student), “Find the Missing Addend” (1 copy per student) Optional Printable Student Resource: “Subtraction Cards” (1 copy per small group), “Number Cards” (2 copies per small group)
Lesson Plan Description
This fully scripted First Grade half day lesson plan is broken down into 2 separate segments (30-60 minutes each). These lessons address Operations and Algebraic Thinking: Understand subtraction as an unknown-addend problem. For example, subtract 10 – 8 by finding the number that makes 10 when added to 8 (1.OA.4). These lessons include: a review of the addition commutative property, practice flipping around addition problems into subtraction problems, using manipulatives to solve subtraction problems, practice finding missing addends to help solve a subtraction problem, an exit slip as an optional assessment component, and an activity using cards and equations where students will flip subtraction problems into addition problems to help find a solution.
- Segment 1: Students will review the Addition Commutative Property, show subtraction as an unknown-addend problem using manipulatives, and will display their understanding of using subtraction as an unknown-addend problem.
- Segment 2: Students will subtract by turning the problem into an addition problem.
These lessons can be taught over the span of a half day or you can use the lessons independently, broken up over several days.