Everyday Mathematics Grade 3, Unit 9: Multidigit Operations
In this unit, your child adds and subtracts larger numbers within 1,000 and multiplies one-digit numbers by multiples of 10, such as 5 x 60 = 300. Children use place value to choose a strategy and check whether answers make sense. It brings the year's multiplication facts together with adding and subtracting, closing third grade with a strong sense of how big numbers work.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
What is my child learning in Unit 9?
- Adding and subtracting three-digit numbers with confidence, including subtracting across zeros, as in 600 - 248, and checking with addition. Learn more about adding within 1,000: Adding within 1,000 · Learn more about subtracting within 1,000
- Multiplying one-digit numbers by 10, 20, 30, and so on up to 90, using place value, such as 7 x 30 = 210. Learn more: Multiplying by tens, like 4 x 70
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 245 + 132?
- 113
- 277
- 377
How you can help
- Add the page counts of two chapter books, such as 248 and 176, and then ask how many more pages the longer book has.
- Figure out costs at the store with tens: if a bag of pretzels costs 90 cents, ask how many cents 3 bags cost and how your child knows.
- Ask your child to estimate first, then solve, then compare, such as deciding 403 - 198 is about 200 before finding the exact answer, 205.
Where kids can get stuck
- Getting tangled when subtracting across zeros, as in 400 - 156, and skipping a regrouping step.
- Forgetting to add a regrouped ten or hundred, so 456 + 278 comes out as 624 instead of 734.
- Writing the wrong number of zeros when a fact already ends in zero, so 5 x 80 becomes 40 or 4,000 instead of 400.
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 ones for 1 ten, or 10 tens for 1 hundred, and back.
- sum
- The answer to an addition problem.
- difference
- The answer to a subtraction problem.
- place value
- The value a digit has because of its place, like the 4 in 470 meaning 4 hundreds.
- hundreds
- The place that tells how many groups of 100 are in a number.
- multiple of 10
- A number you say when counting by tens, like 30, 70, or 90.
- estimate
- A close guess, often made by rounding, to check whether an answer makes sense.
- product
- The answer to a multiplication problem.
Want to help your child master working with bigger 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.
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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 Everyday Mathematics Grade 3 Unit 9 cover?
Everyday Mathematics Grade 3 Unit 9 covers these math standards. Each one links to what it means, sample questions, and teaching strategies.
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.