Lesson Objectives

- Demonstrate the ability to construct a number line for the whole numbers
- Learn how to add two whole numbers using a number line
- Learn how to add more than two whole numbers using a number line

## How to Add Whole Numbers using a Number Line

At this point, you should be fairly comfortable with creating a number line that represents the whole numbers. Recall the whole numbers start with a 0 and increase in increments of 1 indefinitely.

Whole Numbers: {0,1,2,3,4,5,...} You should also be fairly comfortable with single-digit addition. This process can be visualized using a number line to count. Using a number line to perform addition may seem trivial right now, but this method will help enormously when we get to adding and subtracting integers.

Whole Numbers: {0,1,2,3,4,5,...} You should also be fairly comfortable with single-digit addition. This process can be visualized using a number line to count. Using a number line to perform addition may seem trivial right now, but this method will help enormously when we get to adding and subtracting integers.

### Adding two Numbers on a Number Line

- Start on the number line at the leftmost number of the addition problem
- Move to the right by the number of units being added

- Start out at the number 3, the leftmost number of the addition problem
- Move to the right by 4 units
- We end up at 7, which is our answer
- 3 + 4 = 7

- Start out at the number 4, the leftmost number of the addition problem
- Move to the right by 14 units
- We end up at 18, which is our answer
- 4 + 14 = 18

### Adding more than two Numbers on a Number Line

- Start on the number line at the leftmost number of the addition problem
- Move to the right by each number of units being added

- Start out at the number 5, the leftmost number of the addition problem
- Move to the right by 3 units
- We end up at 8
- Move to the right by 5 units
- We end up at 13, which is our answer
- 5 + 3 + 5 = 13

#### Skills Check:

Example #1

Find each sum using a number line.

12 + 8

Please choose the best answer.

A

20

B

4

C

16

D

22

E

10

Example #2

Find each sum using a number line.

4 + 9 + 6

Please choose the best answer.

A

13

B

19

C

21

D

17

E

11

Example #3

Find each sum using a number line.

7 + 11 + 3

Please choose the best answer.

A

22

B

15

C

19

D

21

E

13

Congrats, Your Score is 100%

Better Luck Next Time, Your Score is %

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