Balance Three-Digit Addition Equations

Do you remember how to balance equations? 🤔

When we** balance an equation,** we make sure the value on each side of the equals sign is equal.

How do we balance an equation with a missing part?

Let’s review! 👇

✅ The first step is to **simplify.**

Add together any two numbers that you can!

Remember to rewrite the equation on a new line after you simplify.

We can figure out the missing number by using a Part-Whole diagram.

What's missing, the **part **or a **whole?**

To find the **missing part **we subtract the part we know (8) from the whole (15)!

15 - 8 = 7

Now, we can fill in the missing number in our original equation:

10 + 5=7+ 8

Great job! 💪

Okay, let’s try this with three-digit numbers.

Let’s try this one out:

152 + 3=____ + 10

Let’s start by **simplifying.** Add and rewrite the equation:

Now, let's think about our Part-Whole Diagram. What's missing?

To find a **missing part,** we subtract the **part we know **from the **whole.**

Great! Now let's subtract! 🤓

155-10=145

We can fill in the blank now!

152 + 3=145+ 10

The equation is balanced!

Let’s try another one!

_____ + 20=326 + 15

Where do we start! Adding the equation that is complete!

Now, we can use a Part-Whole diagram:

Let's subtract.

341-20=321

This means our balanced equation is:

321+ 20=326 + 15

You’ve got it! 🤗

Review the basics of balancing equations here:

Good work! 🎉 Now, you can move on to practice!

Teachers:

Password-Free Login!🧚♀️

Scannable **auto login passes** make it easy for your students to login anywhere (even young learners on shared devices).

2,500+ Effective Self-Paced Lessons

Step-by-step, adaptive, mobile-friendly lessons written to grade help students learn (and relearn) Common Core skills with less effort.

Time-Saving Teacher Tools

Turn your old printables and papers into self-grading worksheets that auto assign extra work for students who fail! Even create your own adaptive quizzes. Access all tools without limits.

Question Bank

View and build off over 2.5k+ lessons, 20k+ questions, and 200+ self-grading worksheets in the growing community library.

Student Analytics

Review student progress from the teacher profile.

Assignment Tools

Set a schedule of lessons. Student progress auto-syncs for Google Classroom users.

Trusted by over 100k students, parents, and teachers each month.

Parent

Teacher

Up to 5 students

$39.99 / Year

$6.99 / Month$3.33 / Month

You save $43.89 with the annual plan

7 day free trial