1.4 Adding Integers1.4 Adding Integers

Standards: NS 1.2 and AF 1.3Objective: Add Integers using

Rules

Adding IntegersAdding Integers

• Use the number line to find the sum.

Example:

-3 + (-5)-3 + (-5)

-3 + -5 = -8

- - - + - - - - - = -8

-7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6

Adding IntegersAdding Integers

• Use the number line to find the sum.

Example:

-9 + 6 -9 + 6

- - - - - - - - - -9

+ + + + + + + 6

-3

-7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6

Adding IntegersAdding Integers

Use the + and – to show the work.

• -4 + (-6)

• 4 + (-6)

• -4 + 6

-7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6

Adding IntegersWe are going to predict patterns and make

rules based on what we notice.

Then, we are going to simplify variable expressions.

Adding IntegersAdding IntegersSolve the problems by using + and – to show your work.

1) 4 + 5

2) 16 + 13

PredictPredict: What do you notice about your answers? What rule can we make?

Adding IntegersAdding Integers

Rule 1Rule 1:

Adding positives will give you a positive.

++ + ++ = ++

Adding IntegersAdding IntegersSolve the problems by using + and – to show your work.

1) -12 + (-3)

2) -5 + (-17)

PredictPredict: What do you notice about your answers? What rule can we make?

Adding IntegersAdding Integers

Rule 2:Rule 2:

Adding negatives will give you a negative.

- + - = -

Adding IntegersAdding IntegersSolve the problems by using + and – to show your work.

1) -5 + 8

2) -6 + 13

3) 10 + (-7)

PredictPredict: What do you notice about your answers? What rule can we make?

Adding IntegersAdding Integers

Rule 3:Rule 3:

Adding a BIGGER positive and smaller negative will give you a positive.

TAKE THE SIGN OF THE BIGGER NUMBER.

++ ++ -- == ++

Adding IntegersAdding IntegersSolve the problems by using + and – to show your work.

1) -4 + 1

2) -11 + 3

3) 12 + (-17)

PredictPredict: What do you notice about your answers? What rule can we make?

Adding IntegersAdding Integers

Rule 4Rule 4:

Adding a smaller positive and BIGGER negative will give you a NEGATIVE.

TAKE THE SIGN OF THE BIGGER NUMBER.

++ ++ -- == --

Adding IntegersAdding Integers

Solve. 1) -9 + 14

2) -7 + -2

3) 4 + (-11)

4) 6 + (-2) + 3 + (-8)

Simplify ExpressionsSimplify Expressions

Simplify the expressions by combining like terms.

1) 4n + (-6n) + 3

2) 21w + (-17w) + 6w

3) 5x + (-2x) + 7

Evaluate ExpressionsEvaluate Expressions

Evaluate (solve) by combining like terms and substituting.

1) -5x + 14x + (-6x) when x = 2

2) 8x + (-7) + (-5x) when x = 2

Adding IntegersAdding Integers

You can use integer addition in real-life situations when you know the direction and the amount of change in a quantity.

Adding IntegersAdding Integers

1) The temperature at 4 pm Tuesday was 14° Fahrenheit. By 6 am Wednesday, the temperature had dropped 21°. What was the temperature?

Adding IntegersAdding Integers

Adding IntegersAdding Integers