Grade 3 · Number & Operations in Base Ten · MAT-03-NBT-005
Multiply One-Digit Numbers by Multiples of 10
Represent multiply one-digit numbers by multiples of 10 with words, symbols, diagrams, or models appropriate to Grade 3.
Learning objectives
What you should be able to do
- Represent multiply one-digit numbers by multiples of 10 with words, symbols, diagrams, or models appropriate to Grade 3.
- Solve problems involving multiply one-digit numbers by multiples of 10 accurately and explain why the method works.
- Check results for reasonableness using a second representation, inverse relationship, benchmark, or property when appropriate.
Prerequisite check
Make sure the foundation is ready.
Checks conceptual readiness before new Grade 3 reasoning.
Checks whether prior skills are available for use, not only recalled by name.
Learn
Build the idea from meaning, not memorization.
Meaning of Multiply One-Digit Numbers by Multiples of 10
Multiplying a one-digit number by a multiple of 10 combines a basic fact with place value.
A reliable reasoning strategy
Write the multiple of 10 as tens, multiply the number of tens, then convert back to a whole-number value.
Representations that should agree
For example, several groups of 4 tens are the same as several groups of 40. A correct model, equation, verbal explanation, or diagram should preserve the same quantities and relationships.
How to check the result
Check whether the answer fits the quantities, units, and structure of the problem. Use a second representation or inverse relationship when available, and explain what would make an answer unreasonable.
Interactive math lab
Change it. See what stays true.
Base-Ten Lab
Change hundreds, tens, and ones and watch the total rebuild from place value.
- build a model
- change one quantity
- predict before calculating
- explain why the result changes
Worked examples
Twenty different ways to see the concept work.
Find 3 × 20.
3 × 20 = 60Think of 20 as 2 tens, multiply 3 × 2, then interpret the result as tens.
Find 4 × 30.
4 × 30 = 120Think of 30 as 3 tens, multiply 4 × 3, then interpret the result as tens.
Find 5 × 40.
5 × 40 = 200Think of 40 as 4 tens, multiply 5 × 4, then interpret the result as tens.
Find 6 × 50.
6 × 50 = 300Think of 50 as 5 tens, multiply 6 × 5, then interpret the result as tens.
Find 7 × 60.
7 × 60 = 420Think of 60 as 6 tens, multiply 7 × 6, then interpret the result as tens.
Find 8 × 70.
8 × 70 = 560Think of 70 as 7 tens, multiply 8 × 7, then interpret the result as tens.
Find 9 × 80.
9 × 80 = 720Think of 80 as 8 tens, multiply 9 × 8, then interpret the result as tens.
Find 2 × 90.
2 × 90 = 180Think of 90 as 9 tens, multiply 2 × 9, then interpret the result as tens.
Find 3 × 10.
3 × 10 = 30Think of 10 as 1 tens, multiply 3 × 1, then interpret the result as tens.
Find 4 × 20.
4 × 20 = 80Think of 20 as 2 tens, multiply 4 × 2, then interpret the result as tens.
Find 5 × 30.
5 × 30 = 150Think of 30 as 3 tens, multiply 5 × 3, then interpret the result as tens.
Find 6 × 40.
6 × 40 = 240Think of 40 as 4 tens, multiply 6 × 4, then interpret the result as tens.
Find 7 × 50.
7 × 50 = 350Think of 50 as 5 tens, multiply 7 × 5, then interpret the result as tens.
Find 8 × 60.
8 × 60 = 480Think of 60 as 6 tens, multiply 8 × 6, then interpret the result as tens.
Find 9 × 70.
9 × 70 = 630Think of 70 as 7 tens, multiply 9 × 7, then interpret the result as tens.
Find 2 × 80.
2 × 80 = 160Think of 80 as 8 tens, multiply 2 × 8, then interpret the result as tens.
Find 3 × 90.
3 × 90 = 270Think of 90 as 9 tens, multiply 3 × 9, then interpret the result as tens.
Find 4 × 10.
4 × 10 = 40Think of 10 as 1 tens, multiply 4 × 1, then interpret the result as tens.
Find 5 × 20.
5 × 20 = 100Think of 20 as 2 tens, multiply 5 × 2, then interpret the result as tens.
Find 6 × 30.
6 × 30 = 180Think of 30 as 3 tens, multiply 6 × 3, then interpret the result as tens.
Practice
Guided practice with hints
01Find 9 × 50.
Hint: Write the multiple of 10 as tens, multiply the number of tens, then convert back to a whole-number value.
Answer: 450
02Find 2 × 60.
Hint: Write the multiple of 10 as tens, multiply the number of tens, then convert back to a whole-number value.
Answer: 120
03Find 3 × 70.
Hint: Write the multiple of 10 as tens, multiply the number of tens, then convert back to a whole-number value.
Answer: 210
04Find 4 × 80.
Hint: Write the multiple of 10 as tens, multiply the number of tens, then convert back to a whole-number value.
Answer: 320
05Find 5 × 90.
Hint: Write the multiple of 10 as tens, multiply the number of tens, then convert back to a whole-number value.
Answer: 450
06Find 6 × 10.
Hint: Write the multiple of 10 as tens, multiply the number of tens, then convert back to a whole-number value.
Answer: 60
Practice
Independent practice
01Find 5 × 70.
Answer: 350
02Find 6 × 80.
Answer: 480
03Find 7 × 90.
Answer: 630
04Find 8 × 10.
Answer: 80
05Find 9 × 20.
Answer: 180
06Find 2 × 30.
Answer: 60
07Find 3 × 40.
Answer: 120
08Find 4 × 50.
Answer: 200
Common mistakes
Learn to catch the error, not just the answer.
Name the number of tens first, multiply, then translate the tens back to standard form.
Reconnect the answer to multiply one-digit numbers by multiples of 10 and verify that the model, calculation, and label describe the same quantity.
Applications & challenge
Use the idea beyond a single exercise.
Applications
- Find costs or quantities packed in groups of tens.
- Use multiply one-digit numbers by multiples of 10 to interpret or solve a Grade 3 situation with quantities, diagrams, measurements, or data.
Challenge problems
Find 9 × 90.
810
Find 2 × 10.
20
Find 3 × 20.
60
Find 4 × 30.
120
Flashcards
Retrieve it from memory.
Flashcards
Card 1 of 4
Game mode
Multiply One-Digit Numbers by Multiples of 10 Challenge
Solve and explain Grade 3 problems involving multiply one-digit numbers by multiples of 10 without relying on answer guessing.
Practice
Mastery check
01Find 5 × 20.
Answer: 100
02Find 6 × 30.
Answer: 180
03Find 7 × 40.
Answer: 280
04Find 8 × 50.
Answer: 400
05Find 9 × 60.
Answer: 540
06Find 2 × 70.
Answer: 140
07Find 3 × 80.
Answer: 240
08Find 4 × 90.
Answer: 360
Terminology
Words to know
- multiple of 10
- A number made of whole tens.
- place-value scaling
- Changing value by a factor of ten through place value.
Continue learning
Connected concepts
Curriculum references
Standards and instructional references
California Common Core State Standards for Mathematics — Grade 3, 3.NBT.3
Primary standards alignment for Multiply One-Digit Numbers by Multiples of 10.2023 Mathematics Framework for California Public Schools
Instructional emphasis on reasoning, representations, problem solving, and equitable access.