This is the last post (for now, at least) in our If Not Methods series about how to help children figure out tough calculations.
By the time students reach the topic of multiplying fractions, they have become well-practiced at following rules. After some of the complex procedures they’ve learned, a simple rule like “tops times tops, and bottoms times bottoms” comes as a relief.
But we know that relying on rules like that weakens understanding, just as relying on crutches weakens physical muscles.
If we want our students to think, to make sense of math, to figure things out, what can we do with a problem like 5/6 × 21 ?