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Common Core Math3rd GradeNumbers in Base Ten

3.NBT.3: Multiply by Multiples of 10

Also written as 3.NBT.A.3 and CCSS.MATH.CONTENT.3.NBT.A.3 · Cluster: Use place value understanding and properties of operations to perform multi-digit arithmetic.

Make a 3.NBT.3 WorksheetAll 25 3rd Grade Math Standards

The Official Wording

Multiply one-digit whole numbers by multiples of 10 in the range 10-90 (e.g., 9 × 80, 5 × 60) using strategies based on place value and properties of operations.

Common Core State Standards, Grade 3, Number & Operations in Base Ten · Read it at the source · Checked October 14, 2026

What 3.NBT.3 Means in Plain English

Third graders multiply a single digit by 20, 30 and on up to 90, like 4 × 30 or 6 × 70. The key is the language: 70 is 7 tens, so 6 × 70 is 6 groups of 7 tens, which is 42 tens, or 420.

“Just add a zero” gets the answer but hides the reason, and it misleads students once decimals arrive. These products are the building blocks of 4th-grade multiplication, where 23 × 4 is 20 × 4 plus 3 × 4 (4.NBT.5).

3.NBT.3 I Can Statements

  • I can explain 6 × 70 as 6 groups of 7 tens.
  • I can use a basic fact to multiply by a multiple of 10.
  • I can explain why the product ends in zero.

3.NBT.3 Worked Example

A fact students already know, 6 × 7, carried into the tens.

Problem

Find 6 × 70.

6 × 70 as tens
  1. 70 is 7 tens. So 6 × 70 is 6 groups of 7 tens.6 × 70 = 6 × 7 tens
  2. I know 6 × 7 = 42, so six groups of 7 tens is 42 tens.6 × 7 tens = 42 tens
  3. 42 tens is 4 hundreds and 2 tens.42 tens = 420
  4. Written with the associative property, the 10 waits until the end.6 × (7 × 10) = (6 × 7) × 10 = 420
Answer6 × 70 = 420

Check it: Count by 70s six times: 70, 140, 210, 280, 350, 420.

Common Mistakes with 3.NBT.3

Dropping the tens

6 × 70 = 42

Try this: Say the unit out loud every time: six times seven tens is forty-two tens, and forty-two tens is 420.

Losing a zero when the fact ends in 0

5 × 80 = 40, because 5 × 8 = 40 “already has the zero”

Try this: Keep the tens as a unit: 5 × 8 tens is 40 tens, and 40 tens means 400, not 40.

Multiplying by 0 as if it were 1

4 × 30 = 124, because “4 × 0 is 4”

Try this: Show 4 × 30 as four rows of three ten-rods. There are no loose ones anywhere, so the ones digit must be 0.

Where 3.NBT.3 Fits

Comes Before1.NBT.2Know that 10, 20, 30 and on to 90 mean one to nine tens and 0 ones.2.NBT.2Skip-count by 10s and 100s within 1000.
Alongside3.OA.5Use the associative property: 6 × (7 × 10) = (6 × 7) × 10.3.OA.7Know the one-digit facts these products are built from.
Comes Next4.NBT.5Multiply multi-digit numbers with partial products like 20 × 4.5.NBT.2Explain the pattern of zeros when multiplying by powers of 10.

Practice 3.NBT.3

Multiplication Worksheet GeneratorFree ToolOne-digit numbers times multiples of ten, like 6 × 70 and 9 × 80, with an answer key. Have students write each product as tens first: 42 tens.× 10 to 90One-digit factorAnswer key
Make a Worksheet

Quick Check

  1. 7 × 40
  2. 9 × 60
  3. A box holds 50 crayons. How many crayons are in 8 boxes?

3.NBT.3: Other Names

3.NBT.33.NBT.A.3CCSS.MATH.CONTENT.3.NBT.A.3

Common Core State Standards © Copyright 2010. National Governors Association Center for Best Practices and Council of Chief State School Officers. All rights reserved. Official wording from the Common Core State Standards PDFs at corestandards.org, last checked October 14, 2026. The explanation, I can statements, example, mistakes and practice on this page are EMStudio’s own, written beside the official wording. They are not part of the standard.