Number Line Addition Lesson

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

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Skills Check: