Addition and Subtraction Within 1000: Partial Sums, Decomposing, Counting Up, and Open Number Lines3rd Grade • 2 Lesson Plans with a Bonus Game/Activity
Subject: Math, Numbers and Operations in Base Ten
Type: 2 Lesson Plans with a Bonus Game/Activity
Skills: Adding and Subtracting Within 1000, Expanded Form, Value of Digits, Partial Sums, Decomposing, Counting Up, and Open Number Lines
File Type: PDF Document
Materials Needed: blank paper (6 pieces per student), pencils & crayons/colored pencils, class dry erase board (large enough for 2 people to work at a time) -or- personal dry erase boards (1 per team), dry erase markers, addition or subtraction problems within 1000 (use any sheet of problems), and document camera or whiteboard
Printable Resources: Optional: “Exit Slips” (optional assessment component) (1 copy per student); Optional: “Partial Sums and Decomposing Practice” (1 copy per student); Optional: “Adding and Subtracting Within 1000: Partial Sums and Decomposing” (1 copy per student); Optional: “Adding and Subtracting: Open Number Lines Practice” (1 copy per student); Optional: “Adding and Subtracting Within 1000: Open Number Lines” (1 copy per student); Optional: “Adding and Subtracting: Open Number Lines” notes (1 copy to project for class to see); Optional: “Number Line Hops Face Off” game directions (1 copy to display for the class -or- 1 copy per student)
Lesson Plan Description
Third Grade half day of math lesson plans containing 3 separate segments (30-60 minutes each) addressing Numbers in Base-Ten: adding and subtracting within 1000 (3.NBT.2). These lessons include: key vocabulary/terms, helpful student notes for reference, guided and independent practice of addition and subtraction methods (partial sums, decomposing, counting up, and open number lines), and a game to reinforce the concept of adding and subtracting within 1000 using an open number line.
- Segment 1: students will use expanded form to decompose a number and identify the value of the digits. They will use this knowledge to add using the partial sums method and subtract using the decomposing method.
- Segment 2: students will add and subtract within 1000 using open number lines.
- Segment 3: students will reinforce their knowledge of the value of digits and place values by adding and subtracting within 1000 using open number lines.
These lessons can be taught over the span of a half day or you can use the lessons independently, broken up over several days.