5th Grade · Number & Operations in Base Ten
5.NBT.A.1: Understand place value with decimals, like 0.09 is 1/10 of 0.9
5.NBT.A.1 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
Recognize that in a multi-digit number, a digit in one place represents 10 times as much as it represents in the place to its right and 1/10 of what it represents in the place to its left.
In plain words
Understand place value with decimals, like 0.09 is 1/10 of 0.9.
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
How many hundredths are in 1 tenth?
- 10
- 1/10
- 100
Where students can get stuck
- Believing the pattern works only for whole numbers, so they know 70 is ten times 7 but not how 0.7 and 0.07 relate.
- Mixing up the direction, so they say the 4 in 0.04 is worth more than the 4 in 0.4.
- Treating the decimal point as a wall, reading 3.33 as "three and thirty-three" instead of 3 ones, 3 tenths, and 3 hundredths.
Effective teaching strategies
- Draw a place-value chart with columns from hundreds to hundredths, and have students slide a digit one column left to show it becomes worth 10 times as much.
- Ask students to shade 4 tenths and 4 hundredths on a 10-by-10 grid and say how many times as large the first amount is.
- Have students read 3.33 as 3 ones, 3 tenths, and 3 hundredths, then explain how each 3 compares with the 3 beside it.
Units that teach this standard
Find where 5.NBT.A.1 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 Math²
Everyday Mathematics
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 What each digit is worth, including decimals 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.