Use A Number Line
Goal:
Goal:
How do you use a number line to add one-digit and two-digit numbers?
One of the best tools in your math toolbox is a number line.
A number line can help you solve many different types of math problems. In this lesson, we will use a number line for addition problems! Click through the slides below to learn how.
When we use a number line to add, we start with the greater addend and count up the second addend. Let’s try it. Look at this problem:
16 + 9
Which addend is greater? That’s right! 16 is greater than 9. Put your finger on the 16 on the number line.
What is the other addend? Great! We will be adding 9 to 16, which means we will jump forward on the number line 9 times starting at number 16. Let’s go!
What number did we land on? That’s right -- 25. 16 + 9 \({ = }\) 25!
Let’s try another one.
Here is our addition problem:
8 + 21
First, we need to find the greater addend. Which number is greater, 8 or 21?
That’s right! 21 is greater. Put your finger on the 21 on the number line.
Do you remember what we do next?
We need to jump forward on the number line 8 times. Let’s go!
What number did we land on?
That’s right -- 29. 8 + 21 \({ = }\) 29!
You are doing so well! Let’s try one more.
Here is our addition problem:
18 + 5
Which addend is greater?
In this addition problem, the first addend is greater. We will start on number 18.
How many spaces do we jump forward?
We will jump forward 5 spaces!
The number we landed on is our answer: 18 + 5 \({ = }\) 23.
Solve the addition problem using the number line.
19 + 8
- 27
- 28
- 29
Correct!
Incorrect. Remember to start on the greater addend. Start on 19, and jump forward 8 more.
Incorrect. Start on the greater addend. When you start on 19 and jump forward 8 more, what do you land on?
Summary
Questions answered correctly:
Questions answered incorrectly:
It’s time to use a number line to add more two-digit and one-digit numbers.
Click the arrow to use this tool to help at a diner!