Explaining Mathematical Reasoning
With teacher prompting, explain and justify mathematical reasoning using drawings, number sentences, or words
What a learner can do afterwards
- Explain a solution strategy using a drawing or number sentence (e.g. 'I made ten first, then added the rest')
- Justify why an answer is correct by showing an alternative method that gives the same result
- Identify and explain an error in a worked example or a peer's solution
The lesson
Solving a math problem is only half the job. The other half is telling someone how you got there. You can use a drawing, a number sentence, or just words.
Mia has 8 stickers and gets 5 more. She explains: 'I made a ten first. 8 and 2 makes 10. Then I still have 3 left, so 10 and 3 makes 13.'
If a friend's answer looks wrong, look at their steps. Maybe they skipped a number or added the wrong parts. Checking someone's steps helps you find the mistake, not just the wrong answer.
You can show your math thinking with a drawing, a number sentence, or words, and use it to check answers and find mistakes.
Watch it
Where it sits
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.