MyMathKidK-8 Curriculum

Grade 3 Mental Math Worksheets

Master mental math step by step, from basic concepts to advanced problem solving

Common Core: 3.NBT

Watch & Learn

Learning Path

Start with Lesson 1 and work your way through!

1

Break Apart Strategy

Beginner

Break numbers into parts

Break apart addendsAdd in parts
2

Compensation Strategy

Easy

Adjust numbers to make easy math

Round to friendly numbersCompensate
3

Multiplication Patterns

Easy

Use patterns to multiply mentally

Find patternsMultiply by 10, 100
4

Using Properties

Easy

Apply commutative and associative properties

Use commutative propertyUse associative property
5

Mixed Mental Math

Easy

Practice all strategies

Choose best strategyApply all methods

How to solve Grade 3 mental math problems

Real problems from these worksheets, solved one step at a time — the same explanations your child sees when practicing online.

  1. Example 1

    194 + 62 = ?

    1. Line up the numbers by place value.
    2. Add each column from right to left.
    3. Ones: 4 + 2 = 6
    4. Tens: 9 + 6 = 15. Write 5, carry 1.
    5. Hundreds: 1 + 0 + 1 (carried) = 2
    6. The answer is 256.

    Answer: 256

  2. Example 2

    31 + 52 = ?

    1. Break apart both numbers by place value.
    2. 31 = 30 + 1
    3. 52 = 50 + 2
    4. Add the tens: 30 + 50 = 80
    5. Add the ones: 1 + 2 = 3
    6. Combine: 80 + 3 = 83

    Answer: 83

  3. Example 3

    28 + 46 = ?

    1. Break apart both numbers by place value.
    2. 28 = 20 + 8
    3. 46 = 40 + 6
    4. Add the tens: 20 + 40 = 60
    5. Add the ones: 8 + 6 = 14
    6. 14 ones = 1 ten and 4 ones (regrouping)
    7. Combine: 60 + 14 = 74

    Answer: 74

Frequently Asked Questions

Are these Grade 3 Mental Math worksheets free?
All printable Mental Math worksheets on MyMathKid are free to download and print. Answer keys are a premium feature available with a subscription.
How many Mental Math worksheets are available for Grade 3?
There are 5 progressive Mental Math lessons with worksheets for Grade 3, covering skills from foundational concepts to advanced problem solving.
Are these Mental Math worksheets aligned to Common Core?
Yes — Grade 3 Mental Math aligns with Common Core 3.NBT (Number & Operations in Base Ten).
What will my child practice with these Mental Math worksheets?
Your child will practice: Break Apart Strategy, Compensation Strategy, Multiplication Patterns, Using Properties, and more.