Grade 1 · Computational Fluency
Addition and Subtraction to 20
Addition and subtraction to 20 is the computational core of Grade 1. The BC curriculum emphasises understanding of operation and process, not just answer-getting. Students learn three key strategies: counting on, making 10, and using doubles. Number talks are the primary instructional vehicle: short whole-class discussions where students share mental strategies for a single problem and learn from each other.
LESSON VIDEO
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Lesson video
A short walkthrough to play in class or assign for flipped/at-home viewing.
WHAT STUDENTS WILL LEARN
✓Apply mental math strategies: counting on, making 10, and using doubles
✓Understand that addition and subtraction are inverse operations
✓Decompose 20 into parts using concrete materials and pictorial models
✓Solve addition and subtraction problems to 20 in a variety of contexts
✓Participate in whole-class number talks to share and compare strategies
✓Recall basic addition and subtraction facts to 10 with fluency