In a previous lesson, students revisited addition within 1,000 using strategies based on place value, and properties of operations. An algorithm is different from a strategy because it is a set of steps that works every time as long as the steps are carried out correctly. The algorithms introduced in this lesson draw on the grade 2 work within 1,000 in that they show the addition of ones to ones, tens to tens, and hundreds to hundreds. Students should have access to base-ten blocks if they choose to use them.
Activity 1: What is an Algorithm?
- Add within 1,000.
- Relate base-ten diagrams to written algorithms for addition.
- Let’s learn new ways to add.
Materials to Gather
|Activity 1||20 min|
|Activity 2||15 min|
|Lesson Synthesis||10 min|
Teacher Reflection Questions
- Target Numbers (1–5), Stage 6: Add Hundreds, Tens, or Ones (Addressing)
- Five in a Row: Addition and Subtraction (1–2), Stage 8: Add within 1,000 with Composing (Addressing)
- Rectangle Rumble (3–5), Stage 2: Factors 1–5 (Supporting)