When showing math reasoning we often use the words “prove” or “support”. I love the language but I think it’s really important to drive home to students why proving and supporting are so important to learning.
In my grade 5 class we talk about proof as a way of validating thinking. Proof and support are not meant to be persuasive, they’re meant to give legs to our thinking. On occasion, students will have an audience that they have to convince with “proof” or “support”. However, the skill of double-checking is the real thing that we should be driving home with this language. "Are you sure you’re right?“ might be the better question.
Here’s a sample. A dry math computation: 46 X 38
When it’s solved a second way, we can be a little more sure of the answer.
When solved a third time, we can be still more sure of the answer.
When solved a fourth way we can be REALLY sure of the answer.
When used in this way, the words "proof” and “support” inspire gritty thinking and academic rigour. If students can show their answers in a number of different ways, they won’t have to wait for marks or stickers or “WOW!” on their papers to validate their thinking. They’ll KNOW that they’re right.