Reasoning: Convince me – What’s the same? What’s different? Learning objective To be able to identify what is the same and what is different about two mathematical statements and provide a convincing argument.
Links to year 3 problem solving and reasoning pupil target sheet Reasoning I can explain what’s the same and what’s different. I can explain my reasoning using simple words, calculations and diagrams. I can give at least one other example to back up my reasoning.
Teaching notes • The strategy ‘What’s the same? What’s different?’ encourages pupils to look for connections across the items in the set. • You can begin by asking the pupils to compare and contrast two things, but as they become more confident with their reasoning skills extend the set to include more than two items. • Steer pupils towards mathematical conjectures rather than sweeping superficial statements such as ‘They are the same because they are all shapes.’ Example: What is the same and what is different about a cube and a cuboid?
• Share the problem with the pupils. Ask: First, what is the same about both these shapes? – Establish that they are both 3-D shapes. They have the same number of faces, vertices and edges. Both shapes have square faces. • Ask: Now, what is different about both these shapes? – Establish that the cube is made up of six identical square faces whereas the cuboid is made up of rectangle faces. – Model writing up the findings as a table: Same
Different
• • • •
• cube is made up of six identical square faces • cuboid is made up of six rectangular faces
both 3-D shapes the same number of faces the same number of vertices the same number of edges
For pupils – Steps to success 1. 2. 3. 4.
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Look at each item in the set. Think about what is the same across all items in the set. Then think about what is different. Ensure the reasons are mathematical.
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