Reveal Math Grade 4, Unit 2: Addition and Subtraction
In this unit, your child adds and subtracts multidigit whole numbers with the written method in columns, regrouping across places and across zeros, and checks answers by estimating or by using the inverse operation. It builds on the place-value understanding from the base-ten unit and leads into multiplication, where place value matters just as much.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
What is my child learning in Unit 2?
- Adding and subtracting multidigit whole numbers in columns, regrouping across places and zeros, and checking with an estimate or by adding back. Learn more about adding numbers up to a million: Adding numbers up to a million · Learn more about subtracting numbers up to a million
Sample questions to try together
These are real questions from our practice. Tap the speaker to hear one read aloud, or the light bulb for a hint, and talk about the answer together.
Question 1 of 3
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
How you can help
- Total a grocery receipt with your child, adding two or three item prices in columns and comparing the answer with a quick estimate.
- Find how many years ago something happened, like the year a family member was born, by subtracting in columns, then add back to check.
- Compare the lengths of two trips on a map, such as 1,250 miles and 875 miles, and ask your child how much farther the longer one is.
Where kids can get stuck
- Subtracting the smaller digit from the larger in each column, so 63 − 47 comes out as 24 instead of 16.
- Getting stuck subtracting across zeros, as in 4,003 − 1,258, and regrouping only the first zero.
- Lining numbers up by their left edges instead of by place, so the digits of 418 land under the wrong places of 2,375.
Practice makes perfect
Bobby's Math Club has practice problems that adapt to your child’s level, each with a detailed explanation and an easy-to-follow video, so your child can build confidence in these skills one step at a time.
Words your child will hear
- regroup
- To trade 10 of one place for 1 of the next, like 10 ones for 1 ten.
- sum
- The answer to an addition problem.
- difference
- The answer to a subtraction problem.
- estimate
- A close guess found with rounded numbers, used to check whether an answer makes sense.
- inverse operation
- The operation that undoes another, like adding to check a subtraction.
- place value
- The value a digit has because of where it sits in a number.
- digit
- Any one of the ten symbols 0 through 9 that we use to write numbers.
Ready to build your child’s confidence with adding and subtracting big numbers?
In Bobby's Math Club, your child practices these skills 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.
Join the club
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.
Which math standards does Reveal Math Grade 4 Unit 2 cover?
Reveal Math Grade 4 Unit 2 covers this math standard. Each one links to what it means, sample questions, and teaching strategies.
- 4.NBT.B.4: Fluently add and subtract numbers up to a million.
For teachers: Unit names and order vary between editions and districts, so your school’s own materials have the exact sequence. Learn how Bobby's Math Club can help your students grow.