Mathematics
Fractions
Conceptual
10–11 yrs
Multiplication as scaling
乘法作为缩放
Description
Interpret multiplication as scaling (resizing): compare the size of a product to a factor based on the size of the other factor without computing; explain the effect of multiplying by fractions greater than, equal to, or less than 1
Mastery Evidence
- Predict without calculating whether 3/4 × 7 is greater or less than 7
- Explain why multiplying by 5/3 makes a number larger and multiplying by 2/5 makes it smaller
- Relate multiplying a/b by n/n = 1 to the principle of fraction equivalence
Assessment Prompt
If your child multiplies 20 by 1/4, can they predict whether the answer will be bigger or smaller than 20 — and explain why, before doing the calculation?
