5th Grade · Number & Operations in Base Ten
5.NBT.B.7: Add, subtract, multiply, and divide decimals to hundredths
5.NBT.B.7 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
Add, subtract, multiply, and divide decimals to hundredths, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method and explain the reasoning used.
In plain words
Add, subtract, multiply, and divide decimals to hundredths.
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 9
Amara bikes 4.6 kilometers to the library and then 3.85 kilometers to the park. How far does she bike in all?
- 4.31 kilometers
- 7.45 kilometers
- 8.45 kilometers
Where students can get stuck
Add and subtract decimals to hundredths.
- Lining up the last digits instead of the decimal points, so 3.4 + 1.25 becomes 1.59 instead of 4.65.
- Forgetting that ten tenths make a whole, so 2.6 + 1.7 comes out as 3.13 instead of 4.3.
- Subtracting the smaller digit from the larger in each place, so 5.2 - 1.75 comes out as 4.55 instead of 3.45.
Multiply decimals to hundredths.
- Writing 0.2 × 0.3 as 0.6 instead of 0.06, not seeing that two tenths of three tenths is six hundredths.
- Placing the decimal point without checking the size, so 6 × 0.25 comes out as 15 or 0.15 instead of 1.5.
- Multiplying only the whole numbers, so 2.5 × 4 becomes 8 instead of 10, with the 5 tenths left out.
Divide decimals to hundredths.
- Treating 3 ÷ 0.5 like 3 ÷ 2 and answering 1.5, instead of counting how many halves fit into 3, which is 6.
- Losing track of the decimal point when sharing, so 3.6 ÷ 4 comes out as 9 instead of 0.9.
- Writing a remainder instead of going on into hundredths, so 4.5 ÷ 2 ends as 2 remainder 0.5 rather than 2.25.
Effective teaching strategies
- Line up the decimal points, not the last digits, when adding 3.4 and 1.25, and have students write 3.40 so every place holds a digit.
- Have students shade 0.2 across and 0.3 down on a hundredths grid, then count the squares where the shading overlaps to see that 0.2 × 0.3 is six hundredths.
- Ask how many halves fit into 3 for 3 ÷ 0.5, and have students draw 3 wholes cut into halves and count the pieces.
Units that teach this standard
Find where 5.NBT.B.7 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
Everyday Mathematics
Go Math!
i-Ready Classroom Mathematics
Illustrative Mathematics
Into Math
Math Expressions
Reveal Math
Don’t see your curriculum? Contact Bobby and we’ll see if we can help!
Share it with families
Each skill has its own guide for families, with a plain-language look at the skill, 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.