Adding and Subtracting within 1000
Students will add and subtract numbers within 1000 using concrete models or drawings and strategies based on place value.
Key Questions
- Explain how the strategies for adding two-digit numbers extend to three-digit numbers.
- Design a strategy to solve 345 + 128 using an open number line.
- Compare different strategies for subtracting 500 - 230.
Ontario Curriculum Expectations
Suggested Methodologies
Ready to teach this topic?
Generate a complete, classroom-ready active learning mission in seconds.
Planning templates for Mathematics
5E Model
The 5E Model structures lessons through five phases (Engage, Explore, Explain, Elaborate, and Evaluate), guiding students from curiosity to deep understanding through inquiry-based learning.
unit plannerMath Unit
Plan a multi-week math unit with conceptual coherence: from building number sense and procedural fluency to applying skills in context and developing mathematical reasoning across a connected sequence of lessons.
rubricMath Rubric
Build a math rubric that assesses problem-solving, mathematical reasoning, and communication alongside procedural accuracy, giving students feedback on how they think, not just whether they got the right answer.
More in Additive Thinking and Mental Strategies
Addition Strategies: Making Ten and Doubles
Students will practice mental math strategies like making ten and using doubles to solve addition problems within 20.
2 methodologies
Subtraction Strategies: Fact Families
Students will explore the inverse relationship between addition and subtraction using fact families.
2 methodologies
Adding Two-Digit Numbers (No Regrouping)
Students will add two-digit numbers using strategies based on place value and properties of operations, without regrouping.
2 methodologies
Adding Two-Digit Numbers (With Regrouping)
Students will add two-digit numbers with regrouping, understanding when and why to regroup tens.
2 methodologies
Subtracting Two-Digit Numbers (No Regrouping)
Students will subtract two-digit numbers using strategies based on place value, without regrouping.
2 methodologies