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.

### 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
Example 1: Add 3 + 4, using the number line • 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
Example 2: Add 4 + 14, using the number line • 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
Example 3: Add 5 + 3 + 5, using the number line • 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