# Lesson Plan

• Semester 1
• Week 8

## Topic: Using Bar Models:Addition and Subtraction

### “I can” Statements

1. I can solve up to 2-step word problems involving addition and subtraction.

### Common Core Standards

• 3NBT.D8
• Solve two-step word problems using the four operations. Represent these problems using equations with a letter standing for the unknown quantity. Assess the reasonableness of answers using mental computation and estimation strategies including rounding.

### Suggested Workbook Series

• Math in Focus workbook (3A)
Chapter 5 – Using Bar Models: Addition and Subtraction (pages 73 to 92)
• Primary Mathematics workbook (Common Core Edition) (3A)
Chapter 2 – Addition and Subtraction (pages 64 to 74)

### Suggested Activities

1. Associate the terms ‘sum’ and ‘difference’ with the comparison model, e.g. ‘The sum of 35 and 60 is 95 and their difference is 25.’
2. Solve a variety of problems: 1-step word problems, 2-part word problems (1 step for each part), 2-step word problems and non-routine problems to become familiar with the problem-solving process.
3. Work in groups to create 2-step word problems involving addition and subtraction up to 4 digits for other groups to solve.
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