Addition with Unknown Numbers1st Grade • Half Day Lesson Plan
Subject: Math, Operations and Algebraic Thinking
Type: Half Day Lesson Plan
Skills: Determine the unknown whole number in an addition equation relating three whole numbers.
File Type: PDF Document
Materials Needed: pencils, manipulatives: small counting blocks or similar manipulatives, small chips/counters, and small counting bears or similar manipulatives, cup or container to hide/cover counting blocks, student whiteboards, erasers, dry erase markers, and scissors and glue
Printable Resources: Required Printable Resources: “I am a Detective! Find the Missing Number” (page 13) (1 copy per student) (1 for display), “How Many are Hiding?” (1 copy) (1 set per group), “How Many Sprinkles?” (1 copy – cut out before lesson), “How Many Sprinkles Recording Sheet” (1 copy per student) “Missing Number – Around the Room” (1 copy – cut out before lesson), “Missing Number – Around the Room Recording Sheet” (1 copy per student) Optional Printable Student Resources: “Exit Slips” (as an optional assessment component) (1 copy per student)
Lesson Plan Description
This half day lesson plan is broken down into 2 separate segments (60 minutes each) addressing Operations and Algebraic Thinking: Addition with Unknown Numbers (1.OA.8). These lessons include: key addition vocabulary, guided and independent practice of concepts, and 3 activities to reinforce the concept of determining an unknown in an addition equation.
- Segment 1: students will determine the unknown number in an addition equation relating 3 numbers using
manipulatives, count on to determine the unknown number to make an addition equation true, and use subtraction to determine the unknown number to make an addition equation true.
- Segment 2: students will participate in 3 activities, “How Many are Hiding?,” “How Many Sprinkles,” and “Missing Numbers – Around the Room.”
These lessons can be taught over the span of a half day or you can use the lessons independently, broken up over several days.