Lesson objective: Understand that fractions are numbers on a number line that represent a distance from zero.

Students bring prior knowledge that fractions are a quantity formed when a whole is partitioned into b equal parts from 3.NF.A.1. This prior knowledge is extended to understanding that fractions represent a distance from zero on a number line as students place and locate fractions on number lines. A conceptual challenge students may encounter is understanding that a fraction is one number that has a home on the number line like the whole numbers they previously worked with in earlier grade levels.

The concept is developed through work with a number line, which visually illustrates for students fractions as a distance from zero.

This work helps students deepen their understanding of number because it is focused on developing understanding that fractions are numbers that live on a number line just like any other number would.

Students engage in Mathematical Practice 3 (construct viable arguments and critique the reasoning of others) as they explain their reasoning for why Alexa or Jacob is correct.

**Key vocabulary:**

- denominator
- fraction
- numerator
- partition