Illustrative Mathematics Grade 4, Unit 6: Multiplying and Dividing Multi-Digit Numbers
In this unit, your child multiplies and divides multi-digit numbers by building on place value. They use diagrams and partial products to multiply four digits by one digit and two digits by two digits, divide with partial quotients, and practice the column method for adding and subtracting. It follows the comparison unit and leads into angles.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
What is my child learning in Unit 6?
- Adding and subtracting large numbers fluently with the column method, especially when regrouping across zeros. Learn more about adding numbers up to a million: Adding numbers up to a million · Learn more about subtracting numbers up to a million
- Multiplying with diagrams and partial products, like 4 × 1,346 or 64 × 38, and comparing different methods. Learn more about multiplying large numbers by a one-digit number: Multiplying large numbers by a one-digit number · Learn more about multiplying two two-digit numbers
- Dividing up to four-digit numbers by one-digit numbers with partial quotients, and making sense of remainders. Learn more: Dividing with remainders, like 87 ÷ 5
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
- Ask how many crayons are in 14 boxes of 24. Have your child split it as 10 × 24 and 4 × 24, then add 240 and 96 to get 336.
- Share 156 stickers among 4 friends. Ask your child to hand out groups of 10 first, then the rest, and say how many each friend gets.
- Plan a trip budget of $1,000 with $386 already spent. Ask how much is left, and have your child explain each regrouping across the zeros.
Where kids can get stuck
- Subtracting 3,006 − 1,248 by taking 6 − 8 as 2, without regrouping across the zeros.
- Forgetting a partial product, so 64 × 38 loses 60 × 8 and comes out 480 short.
- Skipping the check by multiplying back, so a wrong quotient goes unnoticed.
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
- algorithm
- A step-by-step method for solving a problem, like adding numbers in columns.
- regroup
- To trade 10 of one place for 1 of the next, like 10 tens for 1 hundred.
- partial products
- The smaller products you get by multiplying each place separately, which are then added together.
- partial quotients
- Dividing in chunks, like taking out 10 groups and then 5 more, and adding the chunks.
- quotient
- The answer to a division problem.
- remainder
- The amount left over when a number can't be split into equal groups exactly.
- divisor
- The number you divide by, like 5 in 87 ÷ 5.
Want to help your child master multi-digit multiplication and division?
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 Illustrative Mathematics Grade 4 Unit 6 cover?
Illustrative Mathematics Grade 4 Unit 6 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.