ADDING SUBTRACTING INTEGERS NS 1 2 and AF

ADDING & SUBTRACTING INTEGERS NS 1. 2 and AF 1. 3

Integers n n Whole numbers and their opposites are integers such as 6 and -6. Zero is also a whole number. -6 0 Opposites 6

Negative Numbers Are Used to Measure Temperature

Negative Numbers Are Used to Measure Under Sea Level 30 20 10 0 -10 -20 -30 -40 -50

Negative Numbers Are Used to Show Debt Let’s say your parents bought a car but had to get a loan from the bank for $15, 000. When counting all their money they add in -$15. 000 to show they still owe the bank.

INTRODUCTION TO INTEGERS n We can represent integers using red and yellow counters. n Red counters will represent negative integers, and yellow counters will represent positive integers. Negative integer Positive integer

INTRODUCTION TO INTEGERS n The diagrams below show 2 ways to represent -3. -3 n -3 Represent -3 in 2 more ways.

INTRODUCTION TO INTEGERS n n Each of the following groups of counters represent -3. You may represent -3 by using 3 red tiles and any number of groups of +1 and -1 tiles

INTRODUCTION TO INTEGERS n Tell which integer each group of tiles represents. 1 -2 2

INTRODUCTION TO INTEGERS n Tell which integer each group of tiles represents. -1 -4 +4

INTRODUCTION TO INTEGERS n Tell which integer each group of tiles represents. +5 -4 -3

INTRODUCTION TO INTEGERS n If there are the same number of red tiles as yellow tiles, what number is represented? n It represents 0.

Adding and Subtracting Integers -3 + 4 = -3+4=1

Adding and Subtracting Integers 6 – 10 = -4

Adding and Subtracting Integers -6 + -7 = -13

Adding and Subtracting Integers 12 + -7 = 5

Adding and Subtracting Integers n Three Meanings of the Minus Sign ¡ Subtract n ¡ Negative n ¡ Example: 8 – 5 is read “subtract 5 from 8” Example: 8 – 5 can be read “ 8 and negative 5” The Opposite Of n Example 8 – (-5) can be read “ 8 and the opposite of (-5)” or 8 + 5

Adding and Subtracting Integers -3 – (-4) = Reads -3 “and the opposite of” -4 What is the opposite of -4?

Adding and Subtracting Integers -3 – (-4) = Reads 3 “and the opposite of” -4 -3 – (-4) = 1

Adding and Subtracting Integers 5 – (-9) = Reads 5 “and the opposite of” -9 What is the opposite of -9?

Adding and Subtracting Integers 5 – (-9) = Reads 5 “and the opposite of” -9 What is the opposite of -9? 5 – (-9) = 14

n. Add 3+4 using a number line. +4 -2 n. Add -4 + (-2) -7

On your own -4 + 4 = 0 -6 – 15 = -21 -6 + 13 = 7 2 + -13 = -11 -4 – (-4) = 0 -9 – (-9) = 0