Lesson objective: Use the magnitude of the scaling factor to estimate products .

This lesson helps to build fluency with multiplication of whole numbers and fractions less than one. Tape diagrams and number lines are used here because they support students understanding of predicting whether products will be greater than, less than or equivalent to one based on the magnitude of the scaling factor. This work develops students' understanding that scaling does not always make numbers larger.

Students engage in Mathematical Practice 4 (modeling with mathematics) as they use number lines and visual models to interpret situations involving multiplication of numbers less than one.

**Key vocabulary:**

- scaling