Lesson 1

Positive and Negative Numbers

Students in grade 6 have spent considerable time developing their understanding and fluency with positive numbers. In this lesson, students extend their thinking to negative numbers by exploring temperature and elevation. In these two contexts, zero represents a physical situation (freezing point of water, sea level) and numbers less than zero describe a physical state in the real world. Students abstract temperatures and elevations to positive and negative numbers on a number line (MP2).

Comprehend the words “positive” and “negative” (in spoken and written language) and the symbol “-” (in written language). Say “negative” when reading numbers written with the “-” symbol.
Interpret positive and negative numbers that represent temperature or elevation, and understand the convention of what “below zero” typically means in each of these contexts.
Recognize that the number line can be extended to represent negative numbers.

Let’s explore how we represent temperatures and elevations.

Rulers

Rulers may be helpful to create number lines in the “High Places, Low Places” activity.

I can explain what 0, positive numbers, and negative numbers mean in the context of temperature and elevation.
I can use positive and negative numbers to describe temperature and elevation.
I know what positive and negative numbers are.

Addressing

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.