In this lesson, students review what they learned about negative numbers in grade 6, including placing them on the number line, comparing and ordering them, and interpreting them in the contexts of temperature and elevation (MP2). The context of temperature helps build students’ intuition about signed numbers because most students know what it means for a temperature to be negative and are familiar with representing temperatures on a number line (a thermometer). The context of elevation may be less familiar to students, but it provides a concrete (as well as cultural) example of one of the most fundamental uses of signed numbers: representing positions along a line relative to a reference point (sea level in this case). The number line is the primary representation for signed numbers in this unit, and the structure of the number line is used to make sense of the rules of signed number arithmetic in later lessons.
Lesson overview
 1.1 Warmup: Using the Thermometer (5 minutes)
 1.2 Activity: Fractions of a Degree (5 minutes)

1.3 Activity: Seagulls Soar, Sharks Swim (10 minutes)
 Includes "Are you Ready for More?" extension problem
 1.4 Optional Activity: Card Sort: Rational Numbers (15 minutes)
 Lesson Synthesis
 1.5 Cooldown: Signed Numbers (5 minutes)
Learning goals:
 Interpret signed numbers in the contexts of temperature and elevation.
 Order rational numbers, and justify (orally) the comparisons.
 Plot points on a vertical or horizontal number line to represent rational numbers.
Learning goals (student facing):
 Let's review what we know about signed numbers.
Learning targets (student facing):
 I can compare rational numbers.
 I can use rational numbers to describe temperature and elevation.
Required materials:
 preprinted slips, cut from copies of the blackline master
Required preparation:
 Print and cut up slips from the Rational Numbers Card Sort blackline master.
 Prepare 1 copy for every 3 students.
 Students will need copies of both sets 1 and 2.
 Keep the slips from set 1 (Integers) separate from set 2 (Rational numbers that are not integers) for each group.
 Consider using different colors of paper so sets 1 and 2 are easier to separate.
Glossary:
 absolute value  The absolute value of a number is its distance from 0 on the number line. The absolute value of 7 is 7, because it is 7 units away from 0. The absolute value of 5 is 5, because it is 5 units away from 0.
 negative number  A negative number is a number that is less than zero. On a horizontal number line, negative numbers are usually shown to the left of 0.
 positive number  A positive number is a number that is greater than zero. On a horizontal number line, positive numbers are usually shown to the right of 0.
 Access the complete Grade 7 glossary.
Standards
 This lesson builds on the standard: CCSS.6.NS.CMO.6.NS.C.5MO.6.NS.C.6bMO.6.NS.C.7
 This lesson builds towards the standard: CCSS.7.NS.A.1MS.7.NS.1MO.7.NS.A
IM 6–8 Math was originally developed by Open Up Resources and authored by Illustrative Mathematics, and is copyright 20172019 by Open Up Resources. It is licensed under the Creative Commons Attribution 4.0 International License (CC BY 4.0). OUR's 6–8 Math Curriculum is available at https://openupresources.org/mathcurriculum/.
Adaptations and updates to IM 6–8 Math are copyright 2019 by Illustrative Mathematics, and are licensed under the Creative Commons Attribution 4.0 International License (CC BY 4.0).
Adaptations to add additional English language learner supports are copyright 2019 by Open Up Resources, and are licensed under the Creative Commons Attribution 4.0 International License (CC BY 4.0).
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