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Subtract By Adding

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Subtract By Adding
CCSS.MATH.CONTENT.2.NBT.B.5

Basics on the topic Subtract By Adding

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How Do You Do Addition and Subtraction Mentally?

In this video Imani is helping Mr. Squeaks train for an upcoming track meet! As Mr. Squeaks is running, he wants to know exactly how far he has run. He learns all about the think addition to subtract strategy while training. Watch this video to learn more about how to use think addition to subtract.

What is the Think Addition Strategy?

You may know that there are many strategies to help solve addition equations, but did you know that there are many to solve subtraction equations as well? One of those is the think addition strategy, also known as subtract using addition!

You may be wondering, how does addition help subtraction? Addition and subtraction are related, meaning that we can use what we know about one to help us with the other! When using addition to solve subtraction equations;

  • First: create the subtraction equation

  • Then: think of an addition fact to help you subtract. You can this by looking at the subtraction equation!

  • Next: take the smaller number from the subtraction equation to create the new addition equation

  • Finally: count up from the smaller number to find the answer!

Think Addition to Subtract 2nd Grade - Practice

What is the easiest way to add and subtract numbers? Take a look at the example below and use the think addition or subtract using addition strategy to solve!

Remember to create a new addition equation, and to count up to find the answer. We can create thirty plus what equals forty-six as our new addition equation.

Thirty plus sixteen equals forty-six, which means that forty-six minus thirty also equals sixteen!

Think Addition to Subtract - Summary

Today we learned all about think addition to subtract, which is when you subtract using addition. When using addition to subtract;

  • First: create the subtraction equation

  • Then: Use the smaller number to create the new addition equation

  • Next: Count up to solve

  • Finally: Your answer to the addition equation is also the answer to your subtraction equation!

Looking for extra practice? After this video check out the interactive exercises and a think addition to subtract worksheet.

Transcript Subtract By Adding

: "Gear up, Imani! We've got a track meet to practice for." Imani is helping Mr. Squeaks train for his upcoming track meet. He starts at the twenty-three marker and runs to the ten marker, but far did he actually run? Mr. Squeaks and Imani can "subtract by adding" to figure this out! There are many different strategies and tools to help with addition. Well, there are many for subtraction as well! But, did you know that one of the strategies to help with subtraction is actually using addition? Some people use this strategy because they feel more comfortable adding than subtracting. When using addition to subtract… start with the subtraction equation (...) what is the subtraction equation here? It's twenty-three minus ten. Then, remake it as an addition equation by starting with the smaller number. Our addition equation is ten plus what equals twenty-three. Next, count up from the first number to the answer, twenty-three. You can use many tools or strategies to count up (...) let's use a hundreds chart here. What plus ten equals twenty-three? Finally, the amount you count up is the answer to your subtraction equation. Ten plus thirteen equals twenty-three! That means twenty-three minus ten ALSO equals thirteen. Mr. Squeaks sure has been practicing a lot! If he just sprinted from the thirty-eight marker to the twenty marker, how many markers did he run? We can subtract by adding to find out! First, set up the subtraction equation. Here it is thirty-eight minus twenty. Then, remake it as an addition equation by starting with the smaller number. That means our equation becomes twenty plus what equals thirty-eight. Next, count up from the first number to the answer, thirty-eight. Remember, there are many ways to solve addition equations, let's try place value this time. What plus twenty IS thirty-eight? Finally, the amount you count on is the answer to your subtraction equation. Twenty plus eighteen equals thirty-eight. That means thirty-eight minus twenty ALSO equals eighteen. Mr. Squeaks is on his final practice sprint before his big meet! If he ran from the forty-six marker to thirty, how far did he run? In order to subtract by adding, remember to set up the equation first. That means we need to solve for forty-six minus thirty. Then, remake it as an addition equation by starting with the smaller number. Which is thirty plus what equals forty-six. Then, solve for the addition equation using a strategy or tool that works for you, this time let's use a number line. What plus thirty equals forty-six? Finally, the amount you count on is the answer to your subtraction equation. Thirty plus sixteen equals forty-six! So, forty-six minus thirty ALSO equals sixteen. Before we see Mr. Squeaks' race, let's review. When using addition to subtract... Start by creating a subtraction equation. Then, remake it as an addition equation by starting with the smaller number. Next, solve for the addition equation using a strategy or tool. Finally, the amount you count on is the answer to your subtraction equation. Now, let's see that race! : "I don't know about this anymore, Imani... : "Woah! Now that's what I'm talking about, thanks Imani!"