Using Number Lines to Add

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Using Number Lines to Add
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Contents

Mr. Squeaks wants to test out the blender he just built. He has some lady finger bananas, strawberries, and blueberries and asks Imani to bring some more of each. In order to see how much of each ingredient he has in all, he will use addition number lines. But Mr. Squeaks doesn’t know how to add using a number line! Thankfully we will learn how to add numbers on a number line.

What is Number Line Addition?

An addition number line is a straight line with numbers spaced apart equally. What is Addition on a Number Line? When we use a number line for addition, that means we are modeling addition on a number line. Using a number line model for addition, helps us keep track of what we are adding easily. In the next section you will learn how to use a number line for addition.

How to Show Addition on a Number Line

Showing addition on a number line is very simple if you follow the steps on how to add numbers on the number line. These steps tell you how to represent addition on number line, or how to use a number line for addition. Here are the steps on how to do addition with number line:

  • Step 1: Find the starting number or the amount we have on the number line
  • Step 2: Count the number we are adding, moving to the right
  • Step 3: Write the number you land on in the total, this is the answer

If you’re still wondering how to use a number line for addition, the next section will show how to add 2 numbers using a number line.

Number Line Addition Example

Here, we need to add four and five using addition using the number line. Let’s use the steps on how to do addition with number line:

  • Step 1: Find the starting number or the amount we have on the number line

number-line-zero-to-twenty-four-plus-five-four-highlighted-addition-number-lines.svg

  • Step 2: Count the number we are adding, moving to the right

number-line-zero-to-twenty-four-plus-five-five-skips-to-the-right-addition-number-lines.svg

  • Step 3: Write the number you land on in the total, this is the answer

number-line-zero-to-twenty-four-plus-five-five-equals-nine-addition-number-lines.svg

Number Line Addition Summary

How do you do addition on a number line? Remember, showing addition on a number line is very simple if you follow the steps on how to add numbers on the number line:

  • Step 1: Find the starting number or the amount we have on the number line.
  • Step 2: Count the number we are adding, moving to the RIGHT.
  • Step 3: Write the number you land on in the total, this is the answer.

Have you practiced yet? On this website you can practice long addition on a number line and find number line addition worksheets along with other activities, and exercises.

Transcript Using Number Lines to Add

Mr. Squeaks is testing out the blender he just built... what better way to test it than to make a smoothie? He has some lady finger bananas, strawberries, and blueberries... and asked Imani to bring some more of each. Let's practice "addition on a number line up to twenty" to help Mr. Squeaks find the total amount of each ingredient. HERE is a number line. A number line is a straight line... with numbers spaced apart equally. This number line shows ZERO on the LEFT and counts up to TWENTY on the RIGHT. We can use a number line to help us find how many bananas Mr. Squeaks has TOTAL. He started with four bananas (...) and Imani brought him five more... so we are adding FOUR plus FIVE. The first step is to find the number FOUR on the number line. (...) Where is the number four on the number line? (...) HERE is the number FOUR. The second step is to count FIVE places to the right, since we are adding FIVE. When ADDING on a number line, we always count to the RIGHT because the number will get bigger as we add. Let's count five places together! one (...) two (...) three (...) four (...) five! The number you stop on is your answer. FOUR plus FIVE is NINE (...) which means Mr. Squeaks has nine lady finger bananas. Next, Mr. Squeaks started with three strawberries (...) and Imani brought him ten more. Let's add THREE plus TEN to see how many strawberries he has total! The first step is to find the number THREE on the number line. Where is the number three on the number line? (...) HERE is the number THREE. The second step is to count TEN places to the right, since we are adding TEN. Let's count ten places together! one (...) two (...) three (...) four (...) five (...) six (...) seven (...) eight (...) nine (...) ten! What number did we stop on? (...) Thirteen. THREE plus TEN is THIRTEEN (...) which means Mr. Squeaks has thirteen strawberries. Last, Mr. Squeaks started with fourteen blueberries (...) and Imani brought him six more. Let's solve FOURTEEN plus SIX to calculate the TOTAL number of blueberries he has! This time, try to use the number line to find the answer on your own! Let's go over how to find the answer together. The first step is to find FOURTEEN on the number line. The second step is to count SIX places to the RIGHT, since we are adding six. Let's count six places together! one (...) two (...) three (...) four (...) five (...) six! The number we stopped on is TWENTY, so FOURTEEN plus SIX is TWENTY... which means Mr. Squeaks has twenty blueberries. Before we see if Mr. Squeaks' blender works, let's summarize. Remember (...) a number line is a straight line with numbers spaced apart equally. We can use a number line to help us add. First, find the starting number or the amount we have on the number line. Second, count the number we are adding, (...) moving to the RIGHT. The number we land on is the answer. Mr. Squeaks is ready to make his smoothie! Uh oh (...) that doesn't sound right!

Using Number Lines to Add Exercise

Would you like to practice what you’ve just learned? Practice problems for this video Using Number Lines to Add help you practice and recap your knowledge.
  • How many bananas do they have altogether?

    Hints

    Use the picture of the number line to help you.

    Start at 2 and count 5 jumps on the number line. The number you end on is the answer.

    Solution

    Mr. Squeaks and Imani have seven bananas!

    • Mr. Squeaks had two bananas, so we find 2 on the number line.
    • We then count 5 jumps forwards because Imani brought five bananas.
    • We will end on 7, so the answer is seven bananas.
    • You could have also found 5 on the number line and counted 2 jumps forwards.
    • We would still end on 7 this way too.
  • How many strawberries do they have?

    Hints

    Remember, you are trying to solve 9 + 6.

    Find 9 on the number line and count 6 jumps forwards.

    Solution

    Mr. Squeaks had nine strawberries and Imani brought six more, so we are solving 9 + 6.

    • First, find 9 on the number line.
    • Next, jump forward 6 spaces, this time highlighting each jump in yellow.
    • We end on 15 so that is our answer. Highlight it in green.
    • Mr. Squeaks and Imani had fifteen strawberries altogether.
    • Also, you can also start at 6 and count 9 jumps forward.
    • You would still land on 15.
    • However, it is often easier to start with the larger number.
  • Can you add the fruit to find the total number of ingredients in each smoothie?

    Hints

    How many pieces of each fruit are there? For example, here we would be adding 2 + 2.

    You can then use a number line to find the total like this.

    2 + 2 = 4

    It is a good idea to start with the larger number.

    Solution

    This number line shows us how to find the total amount of fruit in the mango and peach smoothie.

    • We would start by finding 7 on the number line as this is the larger number.
    • We could then count 2 jumps forwards.
    • We land on 9.
    • So, there are 9 pieces of fruit in this smoothie.
    • We could have also started at 2 and counted 7 jumps forward. We would still land on 9.
    For the blueberry and banana smoothie
    • We would start by finding 13 on the number line as this is the larger number.
    • We could then count 5 jumps forward.
    • We land on 18.
    • So, there are 18 pieces of fruit in this smoothie.
    • We could have also started at 5 and counted 13 jumps forward. We would still land on 18.
    For the pineapple and cherry smoothie
    • We would start by finding 11 on the number line as this is the larger number.
    • We could then count 2 jumps forward.
    • We land on 13.
    • So, there are 13 pieces of fruit in this smoothie.
    • We could have also started at 2 and counted 11 jumps forwards. We would still land on 13.
    For the strawberry and raspberry smoothie
    • We would start by finding 9 on the number line as this is the larger number.
    • We could then count 5 jumps forward.
    • We land on 14.
    • So, there are 14 pieces of fruit in this smoothie.
    • We could have also started at 5 and counted 9 jumps forwards. We would still land on 14.
  • Can you help Mr. Squeaks and Imani with their recipes?

    Hints

    If you were adding 5 + 4, you would find the number 5 and then count 4 jumps forward to reach the answer, 9.

    Start at the larger number and count on the smaller number.

    Solution
    • For smoothie number one, we were adding 15 + 3 to find the total ingredients.
    • First we find 15 on the number line.
    • We then count 3 jumps forwards.
    • We will land on 18, so that is our answer.

    ___________________________________________________

    • To find the total ingredients for smoothie number two, we needed to add 7 + 6 to get a total of 13.
    • To find the total ingredients for smoothie number three, we needed to add 8 + 9 to get a total of 17.
    • To find the total ingredients for smoothie number four, we needed to add 12 + 7 to get a total of 19.
    • To find the total ingredients for smoothie number five, we needed to add 11 + 9 to get a total of 20.
    _______________________________________________________

    Remember:

    • It doesn't matter which number we start with when we are adding, but it is often a good idea to start with the larger number so you do fewer jumps.
  • How many berries do they have?

    Hints

    How many blueberries did Mr. Squeaks have? This is your starting number. We are starting with this number because it is the biggest number.

    How many raspberries did Imani bring? This is the number you are adding on.

    Use the jumps on the number line to help you to find the total number of berries.

    Solution

    They have eleven berries altogether.

    • Mr. Squeaks had 8 blueberries.
    • Imani brought 3 raspberries.
    • Using a number line to help us we start at 8 and count on 3 more.
    • We end on 11, so that is our answer.
    • This problem could also be solved by starting at 3 and counting 8 jumps forwards.
    • We would still land on 11 if we did it this way.
  • Can you help Mr. Squeaks with his challenge?

    Hints

    It is a good idea to start with the larger number when adding.

    Can you use your knowledge of doubles? For example, what pair of numbers do you know that equal 10?

    Solution

    Here are the different ways to make 10, 15 and 20 from this problem.

    For example:

    • To find the answer for 12 + 8:
    • We could find 12 on the number line.
    • We could then jump forward 8 spaces.
    • We will land on 20, so that is our answer.
    Can you think of any other ways you could make 10, 15 or 20?