Adding & Subtracting Integers

Adding Positive Numbers

I have 3 ice cream cones ready

And then I make 4 more…

I could write this as a number sentence 3 + 4 = 7

To understand adding positive and negative numbers we will look at what happens at my ICE CREAM STORE.

When I have positive numbers (ice cream cones) and I want to find the total amount , I count them together. My total is 7.

3 4

Adding Negative Numbers

First to arrive are these Ice Cream Gobblers.

A few minutes later, more Ice Cream Gobblers arrive.

I could write this as a number sentence -2 + (-3) = -5

Here come the Ice Cream Gobblers. Ice Cream Gobblers take our ice cream cones, so we will represent them with negative numbers.

When I have two groups of negative numbers (Gobblers) and I want to find the total amount, I count them together just as I did with the two groups of positive numbers. My total is -5.

-2 -3

Adding Positive and Negative Numbers

Here are my ice cream cones. A few minutes later, 3 Gobblers arrive.

I could write this as a number sentence 4 + (-3) = 1

This morning in my Ice Cream Store, I have ready 4 ice cream cones.

When I am adding two groups that are different, like my positive cones and my negative Gobblers, I have to watch out. The Gobblers will eat the cones. To find out what happens when I put these groups together I look to see which group is bigger. In this case the cones have a bigger amount (4), than the Gobblers (3). Since the bigger amount is 4 and it is positive my final total will be positive. Three Gobblers will eat 3 of my cones so I will only have one left.

4 -3

Adding Positive and Negative Numbers

Here are my ice cream cones. 4 Gobblers came in.

I could write this as a number sentence 2 + (-4) = -2

Yesterday morning in my Ice Cream Store, I had ready 2 ice cream cones.

To find out what happens when I put these different groups together I look to see which group is bigger. In this case the gobblers have a bigger amount (4), than the cones (2). Since the bigger amount is 4 and it is negative my final total will be negative. Two Gobblers will eat 2 of my cones and 2 Gobblers will be hungry.

2 -4

Practice Adding Signed Numbers

-2 + (-2) =

2 + 1 =

3-4

-5 + (-1) =

-6

-3 + 2 =

-1

-2 + (-3) =

-5

2 + (-1) =

1

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Subtracting Positive Numbers

My friend Jennie came in to visit and knocked 2 of my ice cream cones onto the floor.

I could write this as a number sentence 5 - 2 = 3

Today in my Ice Cream Store, I had ready 5 ice cream cones on the counter.

Since Jennie has ruined them, I will need to subtract them from my inventory.

5

2

Subtracting Negative Numbers

Let’s look at my Gobblers. I have two Gobblers at my counter.

My number sentence starts like this -2 – (-1) = -1

This is the operation where most of the confusion lies. When we subtract negative numbers it is the same as adding.

Subtracting a negative Gobbler, means I’m adding a cone. If I give this cone to one of the Gobblers waiting at the counter. I would only have one Gobbler left.

-2 -1Here comes Gobbler Josh, he doesn’t like vanilla so he’s bringing his ice cream back.

But when we subtract a negative we change the - - to a + -2 +1 = -1

+1

Subtracting Negative Numbers

My number sentence starts like this

-2 1 = -1

When two negatives get together they always change to a positive!

Practice Subtracting Signed Numbers

-2 - (-2) = 2 - 1 = 1

0

-5 - (-1) = -4

-3 - 2 = -5

-2 - (-3) = 1

2 - (-1) = 3

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Practice Adding and Subtracting Signed Numbers

-8 + 5 =

-3 + -2 =

-5-3

-500 - 325 = -825

4 – (- 2 ) =

6

-2 - 7 = -9

400 + (-200) =

200

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Verde Learning Center Adding and Subtracting

Integers Tutorial