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Instructor Overview

Students watch a dot get tossed from one number on a number line to the opposite of the number. Students predict where the dot will land each time based on its starting location.

Key Concepts

  • The opposite of a number is the same distance from 0 as the number itself, but on the other side of 0 on a number line.
  • In the diagram, m is the opposite of n, and n is the opposite of m. The distance from m to 0 is d, and the distance from n to 0 is d; this distance to 0 is the same for both n and m. The absolute value of a number is its distance from 0 on a number line.
  • Positive numbers are numbers that are greater than 0.
  • Negative numbers are numbers that are less than 0.
  • The opposite of a positive number is negative, and the opposite of a negative number is positive.
  • Since the opposite of 0 is 0 (which is neither positive nor negative), then 0 = 0. The number 0 is the only number that is its own opposite.
  • Whole numbers and the opposites of those numbers are all integers.
  • Rational numbers are numbers that can be expressed as ab, where a and b are integers and b ≠ 0.

Goals and Learning Objectives

  • Identify a number and its opposite
  • Locate the opposite of a number on a number line
  • Define the opposite of a number, negative numbers, rational numbers, and integers