5th Grade · Number & Operations in Base Ten
5.NBT.A.2: Multiply and divide by 10, 100, and 1,000, and see how the digits shift
5.NBT.A.2 is a 5th grade Common Core math standard in Number & Operations in Base Ten. Here’s what it really covers, and how you can help your students learn it.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
The standard
Explain patterns in the number of zeros of the product when multiplying a number by powers of 10, and explain patterns in the placement of the decimal point when a decimal is multiplied or divided by a power of 10. Use whole-number exponents to denote powers of 10.
In plain words
Multiply and divide by 10, 100, and 1,000, and see how the digits shift.
Sample questions from student practice
These questions from Bobby's Math Club are the kinds of questions your students will see. You can try answering them to see what a student might see.
Question 1 of 3
Amara's family packs rice for a food bank in bags of 1.5 kilograms. How many kilograms of rice are in 10 bags?
- 0.15 kilograms
- 15 kilograms
- 11.5 kilograms
Where students can get stuck
- Using the "add a zero" rule on decimals, so 4.2 × 10 becomes 4.20, which is still 4.2, instead of 42.
- Moving the decimal point the wrong way when dividing, so 6.5 ÷ 10 becomes 65 instead of 0.65.
- Losing count of zeros when the number already ends in one, writing 50 × 100 as 500 instead of 5,000.
Effective teaching strategies
- Use a place-value chart to multiply 4.2 by 10, sliding each digit one column left, so students see the digits move instead of a zero being added.
- Have students predict whether 6.5 ÷ 10 will be larger or smaller than 6.5, then slide the digits one column right to check.
- Rewrite 50 × 100 as 5 × 10 × 100 with students, and have them count every zero from both factors to see why the product is 5,000.
Units that teach this standard
Find where 5.NBT.A.2 lands in the program you teach. Each unit has a guide written for families. Unit names and order vary between editions and districts, so your school’s own materials have the exact sequence.
Bridges in Mathematics
enVision Mathematics
Eureka Math
Eureka Math²
Everyday Mathematics
Go Math!
i-Ready Classroom Mathematics
Illustrative Mathematics
Math Expressions
Reveal Math
Don’t see your curriculum? Contact Bobby and we’ll see if we can help!
Share it with families
Families can read Multiplying and dividing by 10, 100, and 1,000 for a plain-language look at this skill, with three questions to try together and ideas for helping at home.
Help every student practice place value at home
In Bobby's Math Club, students practice at just the right level, with a hint when they need one, a clear explanation after every question, and kid-friendly videos. Unlimited practice is free for every family.
See how it works for teachers
Written by Robert “Bobby” Barnett
Bobby is an award-winning math teacher, the author of Meet Every Learner’s Needs, and the father of two elementary-school math learners. He uses Bobby’s Math Club with his own kids a few times every week. Learn more or contact Bobby.