Eureka Math Grade 2, Module 4: Addition and Subtraction Within 200 with Word Problems
In this unit, your child adds and subtracts within 200, using place value to regroup, which means trading 10 ones for a ten or 10 tens for a hundred. They add up to four numbers, add or take away 10 or 100 in their head, and explain their strategies. Word problems put it all to use before the numbers grow to 1,000 next.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
What is my child learning in Module 4?
- Solving one- and two-step word problems within 100, using tape diagrams to show the parts and the whole. Learn more: One- and two-step story problems within 100
- Adding and subtracting within 100 with mental strategies, like making a ten or counting on from the smaller number. Learn more about adding within 100: Adding within 100 · Learn more about subtracting within 100
- Adding three or four two-digit numbers, choosing an order that makes friendly tens. Learn more: Adding up to four two-digit numbers
- Adding and subtracting within 200 with place value disks or drawings, regrouping 10 tens into a hundred. Learn more about adding within 1,000: Adding within 1,000 · Learn more about subtracting within 1,000
- Adding or taking away 10 or 100 in their head from numbers like 160 or 185. Learn more: Adding or taking away 10 or 100 mentally
- Explaining why a strategy works, such as why 58 + 27 is the same as 60 + 25. Learn more about explaining why addition strategies work: Explaining why addition strategies work · Learn more about explaining why subtraction strategies work
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
What is 80 minus 20?
- 50
- 60
- 70
How you can help
- Add the scores from a few rounds of a card game, and ask your child to look for two numbers that make a friendly ten first.
- Ask for 10 more, 10 less, 100 more, and 100 less than a number like 145 on a walk or ride, and talk about which digit changed.
- Tell a story with bigger numbers, like 120 stickers with 45 used, and let your child draw a tape diagram to find how many are left.
Where kids can get stuck
- Regrouping 10 tens but forgetting to write the new hundred, so 85 + 47 comes out as 32.
- Moving 2 in the wrong direction, so 58 + 27 becomes 60 + 29 instead of 60 + 25.
- Stopping after the first step of a two-step word problem and calling it done.
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
- Trading 10 ones for 1 ten, or 1 ten for 10 ones, to add or subtract.
- tape diagram
- A drawing of bars, like strips of tape, that shows the parts and the whole of a story.
- hundred
- Ten tens, or 100. In 482, the 4 means 4 hundreds.
- addend
- Each number being added. In 5 + 3 = 8, the addends are 5 and 3.
- strategy
- A way of solving a problem, like making a ten or counting on.
- mentally
- In your head, without writing it down or using objects.
- sum
- The answer when you add numbers together.
- difference
- The answer when you subtract; it also tells how much more one amount is.
Ready to build your child’s confidence with adding and subtracting within 200?
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 Eureka Math Grade 2 Module 4 cover?
Eureka Math Grade 2 Module 4 covers these math standards. Each one links to what it means, sample questions, and teaching strategies.
- 2.OA.A.1: Use addition and subtraction within 100 to solve word problems.
- 2.NBT.B.5: Fluently add and subtract within 100.
- 2.NBT.B.6: Add up to four two-digit numbers.
- 2.NBT.B.7: Add and subtract within 1000.
- 2.NBT.B.8: Mentally add 10 or 100 to a given number 100–900.
- 2.NBT.B.9: Explain why addition and subtraction strategies work.
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.