ADDING & SUBTRACTING INTEGERS by Angela GallacherNS 1.2 and AF 1.3

Integers

Whole numbers and their opposites are integers such as 6 and -6.

Zero is also a whole number.

0 6-6

Opposites

Negative Numbers Are Used to Measure Temperature

Negative Numbers Are Used to Measure Under Sea Level

0102030

-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

We can represent integers using red and yellow counters.

Red tiles will represent negative integers, and yellow tiles will represent positive integers.

Negative integer Positive integer

INTRODUCTION TO INTEGERS The diagrams below show 2 ways to

represent -3.

Represent -3 in 2 more ways.

-3 -3

INTRODUCTION TO INTEGERS

You may represent -3 by using 3 red tiles and any number of groups of +1 and -1 tiles

INTRODUCTION TO INTEGERS

Tell which integer each group of tiles represents.

-2+1

+2

INTRODUCTION TO INTEGERS

Tell which integer each group of tiles represents.

-4 -1

+4

INTRODUCTION TO INTEGERS

Tell which integer each group of tiles represents.

-4 +5

-3

INTRODUCTION TO INTEGERS If there are the same number of red tiles as

yellow tiles, what number is represented?

It represents 0.

Zero Pairs

Zero Bank-3 + 4 =

6 – 10 =

-6 + -7 =

12 + -7 =

-3 – (-4) =

5 – (-9) =

To use zero bank get out of slide show!

On your own

-4 + 4 =

-6 – 15 =

-6 + 13 =

2 + -13 =

-4 – (-4) =

-9 – (-9) =

Zero Bank