In this lesson students examine distances between numbers on the number line. First, the need for absolute value is motivated by asking students to come up with a way to find the distance between 2 numbers, \(a\) and \(b\). Then students find numbers that are a given distance away from a number. In the associated Algebra 1 lesson, students begin the work of thinking about absolute value as a function. Interpreting distances between numbers is essential for the work in the Algebra 1 lesson and supports their thinking about absolute value in upcoming lessons.
Students must look for and make use of structure (MP7) when they write expressions for finding the distance between two numbers on a number line.
Lesson overview
- 13.1 Warm-up: Math Talk: How Far? (10 minutes)
- 13.2 Activity: \(a\) and \(b\) (10 minutes)
- 13.3 Activity: It’s That Far Away (20 minutes)
Learning goals:
- Find distances on the number line using subtraction.
Learning goals (student facing):
- Let’s calculate distances between numbers.
Standards:
- This lesson builds towards the standard: CCSS.HSF-IF.C.7.bMS.F-IF.7bMO.A1.IF.C.7
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