4th Grade · Number & Operations in Base Ten
4.NBT.B.4: Fluently add and subtract numbers up to a million
4.NBT.B.4 is a 4th 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
Fluently add and subtract multi-digit whole numbers using the standard algorithm.
In plain words
Fluently add and subtract numbers up to a million.
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 6
A beach crew picked up 1,874 bottle caps on Saturday and 2,153 on Sunday. How many bottle caps did the crew pick up in all?
- 3,927
- 4,027
- 3,974
Where students can get stuck
Fluently add numbers up to a million.
- Lining numbers up by their left edges instead of by place, so 2,375 + 418 comes out as 6,555 instead of 2,793.
- Forgetting to add a regrouped ten, so 4,568 + 1,375 comes out as 5,933 instead of 5,943.
- Writing each column’s whole total instead of regrouping, so 658 + 275 becomes 81,213 instead of 933.
Fluently subtract numbers up to a million.
- Subtracting the smaller digit from the larger in each column, so 6,342 − 2,518 comes out as 4,236 instead of 3,824.
- Getting stuck subtracting across zeros, as in 5,000 − 2,346, and giving an answer like 3,346 instead of 2,654.
- Putting the smaller number on top because it came first in a story problem, writing 2,846 − 5,120 instead of 5,120 − 2,846.
Effective teaching strategies
- Have students write each number on grid paper with one digit per box, so ones sit under ones and tens under tens, before adding 2,375 and 418.
- Model 5,000 − 2,346 by trading 1 thousand for 10 hundreds, then 1 hundred for 10 tens, then 1 ten for 10 ones, and check the answer by adding.
- Ask students to estimate first, such as 50 − 40 for 52 − 38, and compare the exact answer with the estimate to catch an answer like 26.
Units that teach this standard
Find where 4.NBT.B.4 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
Everyday Mathematics
i-Ready Classroom Mathematics
Illustrative Mathematics
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.