Subtracting within 1,000
In 3rd grade, children learn to subtract numbers within 1,000, such as 503 - 267, quickly and accurately, including numbers with zeros like 400 - 156.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
Try these with your child
These are real questions from our 3rd grade 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 543 - 210?
- 333
- 753
- 343
Why this matters
Subtracting bigger numbers is how your child works out how far apart two amounts are, and it turns up whenever something is compared or used up. In 4th grade the same thinking stretches into the thousands, and it is part of most word problems with more than one step. So it is worth the time now. You’ll see it with pages left in a book, how much taller one thing is than another, or money still to save.
If three-digit subtraction trips your child up, adding within 1,000 is a gentler place to practice the same ideas.
Where kids can get stuck
- Subtracting the smaller digit from the larger in every column, so 503 - 267 comes out as 364 instead of 236.
- Losing track when the top number has zeros, so 400 - 156 lands on 254 instead of 244.
- Adding when a question asks how many more, so “How many more is 420 than 285?” comes out as 705 instead of 135.
How you can help
- Ask how many pages are left. If your child is on page 175 of a 312-page book, have them work it out, then check by adding 137 and 175.
- Compare two tall things you read about, such as a 984-foot tower and a 630-foot one, and ask your child how much taller the first is.
- Look at a food label together. If a box of cereal holds 510 grams and you have used 275, ask your child how many grams are left, and how they figured it out.
Bobby's Math Club offers free practice that grows with your child.
Questions parents ask
Why is my child learning more than one way to subtract?
Different numbers suit different ways. For 500 - 498, counting up 2 is quickest. For 763 - 400, taking away 4 hundreds gives 363 straight away. For 503 - 267, a written method helps keep track. Knowing more than one way lets your child pick a sensible path, and the ways check each other.
Is there an easier way to subtract from numbers with zeros, like 400 - 156?
Often, yes. Taking 1 from both numbers keeps the difference the same, so 400 - 156 has the same answer as 399 - 155. That one needs no trading at all, and it is 244. If your child’s class uses a different way, follow that; this is a nice check to try together.
My child adds big numbers easily but gets stuck subtracting. Is that common?
Yes, and it is very common. Subtracting asks more of your child: deciding which number comes first, dealing with zeros, and keeping track of each step. Start with friendlier numbers, like 650 - 230, before ones like 503 - 267. And have your child check each answer by adding it back to the smaller number, which should give the larger one.
Make learning math fun
Bobby's Math Club turns 3rd grade math practice into something fun to do together.
- Free, unlimited practice for every child in your family
- Questions matched to your child’s level, a few minutes a day
- You see their progress and what to work on next
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.
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Join the clubNote for teachers: This skill is covered by Common Core math standard 3.NBT.A.2: “Fluently add and subtract within 1000 using strategies and algorithms based on place value, properties of operations, and/or the relationship between addition and subtraction.” Learn how Bobby's Math Club can help your students grow. (Common Core 3.NBT.2)