Find the Missing Number on a Number Line
Basics on the topic Find the Missing Number on a Number Line
Missing Numbers on a Number Line
In this video Skylar and Henry are going on their annual forest hike! They decide to follow a flower trail to see where it will lead them, but there’s a problem, some of the flowers are missing! They need to learn about missing numbers on a number line while following the trail. Watch this video to learn more about how to find missing addends with a number line.
How Do You Find the Missing Number in a Number Line?
Let’s repeat the definition of a number line:
A number line is a diagram in which numbers are represented as points on a line. They count by a specific number, sometimes by ones, twos, fives. or even tens.
But, what happens when a number is missing? Follow these steps to find missing numbers on a number line:
Step #  What to do 

1  Look at the whole number line. 
2  Look for the number line pattern – What the number line is counting by. 
3  Count using this pattern to find the missing number on the number line pattern. 
4  Reread the number line to make sure it is correct. 
Missing Numbers on Number Lines – Practice
How can you figure out missing numbers using patterns on a number line? Let’s practice filling in the missing numbers on a number line! Our number line includes numbers from 35 to 70.
Can you figure out which numbers are missing from this number line? Remember our steps to find missing numbers on number lines.
Let’s look at the pattern on the number line. The pattern shows incremental steps of +5! Knowing this, we can figure out the missing numbers by skip counting from the last known number. This number line is missing the numbers fortyfive and fiftyfive!
Missing Numbers Number Line – Summary
When solving for missing numbers on a number line;
First: look at the whole number line.
Then: look for the missing number line pattern – what the number line is counting by.
Next: count using this pattern to find the missing number!
Finally: reread the number line again to make sure it is correct.
Looking for extra practice? After watching this video, check out the interactive exercises and worksheets on missing numbers and addends in number lines.
Transcript Find the Missing Number on a Number Line
: "What a cool forest for our annual exploration hike!" : "There's a trail of flowers... let's follow it!" : "We can count them so we don't get lost." : "But, there are some missing... what should we do?" Let's help Skylar and Henry learn about how to "find the missing number on a number line" so they don't get lost! You may have learned about number lines before. A number line is a diagram in which numbers are represented as points on a line. They count by a specific number, sometimes by ones, twos, fives. or even tens. But, what happens when a number is missing? When a number is missing on a number line you can follow four steps... first, look at the whole number line. Then, look for the pattern, or what the number line is counting by. Next, count using this pattern to find the missing number! Finally, reread the number line again to make sure it is correct. Now, let's help Skylar and Henry! After counting flowers, they see that there are some missing! We can put each flower on the number line to find which are missing. To find the missing number using a number line... first, look at the whole number line. Next, look for the pattern, or what the number line is counting by. You can do that by counting the numbers shown! This number line is counting by ones. Then, count using this pattern to find the missing number. Count with me! Twentythree (...) twentyfour (...) twentyfive (...) twentysix (...) twentyseven (...) twentyeight! So, our missing numbers are TWENTYFIVE, TWENTYSEVEN and TWENTYEIGHT. Finally, read the number line again to make sure it is correct. That means if Skylar and Henry fill in those numbers while counting, they won't get lost! After walking for a bit, there is another problem. MORE flowers are missing! We can practice finding the missing numbers to help! First, look at the whole number line. This number line starts at thirtyfive. Then, look for the pattern, or what the number line is counting by. What is this number line is counting by? (...) fives! Next, count using this pattern to find the missing number! Count with me! Thirtyfive (...) forty (...) fortyfive (...) fifty (...) fiftyfive (...) sixty! Our missing numbers are FORTYFIVE and FIFTYFIVE. Finally, read the number line again to make sure it is correct. Skylar and Henry haven't gotten lost yet, right? Oh good, but, what's this? More missing flowers! Let's help one last time. First, look at the whole number line. This number line starts at seventy. Then, look for the pattern, or what the number line is counting by. Can you tell the pattern for this number line? (...) tens! Next, count using this pattern to find the missing number! Count with me. Seventy (...) eighty (...) ninety (...) one hundred! Our missing numbers are eighty and onehundred. Before we see where the flower trail leads to, let's review. Today we learned about how to find the missing number on a number line. Number lines are diagrams that use points to represent the numbers... and that they can count by different patterns! When using a number line to find a missing number... First, look at the whole number line. Then, look for the pattern, or what the number line is counting by. Next, count using this pattern to find the missing number! Finally, read the number line again to make sure it is correct. Now, let's see where the trail leads to! : "A GIANT flower tree." : "Quick, let's take a selfie with the polaroid!"
Find the Missing Number on a Number Line exercise

Number line patterns.
HintsHere is an example of counting by ones:
12, 13, 14, 15
Here is an example of counting by fives:
30, 35, 40, 45
Here is an example of counting by tens:
40, 50, 60, 70
SolutionThe number line patterns count by ones, fives, tens, and fives.

Skylar and Henry go on a hike.
HintsThe first step when a number is missing on a number line is to look at the whole number line.
The second step when a number is missing on a number line is to look for the pattern or what the number line is counting by.
The third step when a number is missing on a number line is to count using this pattern to find the missing number.
The fourth step when a number is missing on a number line is to reread the number line again to make sure it is correct.
SolutionThe number line counts by ones.
 The missing numbers are 46, 49, and 51.

Help Skylar and Henry find the trail.
HintsWhat is the pattern counting by?
Here is an example of counting by fives:
15, 20, 25, 30
What comes after 65 when counting by fives? What comes after 80 when counting by fives?
SolutionThe number line counts by fives.
 The missing numbers are 70 and 85.

Count the flowers.
HintsWhat is the pattern counting by?
Here is an example of counting by tens:
20, 30, 40, 50
What comes after 60 when counting by tens? What comes after 90 when counting by tens?
SolutionThe number line counts by tens.
 The missing numbers are 70 and 100.

What are the steps of finding a missing number on a number line?
HintsThe image provides an example of the first step of finding a missing number on a number line.
The image provides an example of the second step of finding a missing number on a number line.
The image provides an example of the third step of finding a missing number on a number line.
Solution4 steps when a number is missing on a number line:
 Look at the whole number line.
 Look for the pattern or what the number line is counting by.
 Count using this pattern to find the missing number.
 Reread the number line again to make sure it is correct.

Missing numbers.
HintsWhat is the pattern counting by?
Count back by tens from 90 on the number line to find the initial missing number.
SolutionThe number line counts by tens.
 Count back by tens on the number line from 90 to find the initial missing number, 80.
 The missing numbers are 80, 110, and 140.