Illustrative Mathematics Grade 3, Unit 4: Relating Multiplication to Division
In this unit, your child sees how multiplication and division are linked. They solve division as a missing-factor problem, find unknowns in equations, and learn more facts to 10 × 10. They multiply by multiples of 10 and solve two-step problems with all four operations. Next comes fractions, where dividing a whole into equal parts matters.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
What is my child learning in Unit 4?
- Solving story problems about equal groups and arrays with any fact to 10 × 10, such as 56 chairs in 8 rows. Learn more: Multiplying and dividing in story problems
- Finding the unknown number in equations like 8 × ? = 40 or 40 ÷ ? = 5. Learn more: Finding the missing number, like 7 x ? = 56
- Using a multiplication fact to divide, so 9 × 4 = 36 tells them 36 ÷ 4 = 9. Learn more: Using times tables to divide
- Building fluency, recalling facts quickly and correctly, with harder ones like 7 × 8 and 54 ÷ 9. Learn more about knowing the times tables by heart: Knowing the times tables by heart · Learn more about dividing within 100
- Solving two-step problems with all four operations, and writing an equation with a letter for the unknown. Learn more: Story problems with two steps
- Multiplying a one-digit number by a multiple of 10, like 9 × 20 = 180, and explaining it with place value. 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
Ravi finds 16 socks in the laundry. He puts them into pairs, with 2 socks in each pair. How many pairs does he make?
- 8
- 32
- 14
How you can help
- Ask division facts as times questions during a ride, such as what times 7 makes 56, then say the division fact together.
- Pose a two-step snack question, like 3 bags of 10 pretzels shared among 5 people, and ask your child for their plan (6 each).
- Ask how many minutes are in 2 hours and how many in 4 hours, using 60 minutes in each hour (120 and 240).
Where kids can get stuck
- Counting by ones to solve every division problem instead of using a times fact.
- Writing 9 × 20 = 18, forgetting that the 2 means 2 tens.
- Thinking 40 ÷ ? = 5 has no answer because the unknown sits in the middle.
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
- inverse
- The opposite operation; division undoes multiplication.
- unknown factor
- The missing number in a multiplication problem, like the ? in 8 × ? = 32.
- quotient
- The number you get when you divide, like 5 in 20 ÷ 4 = 5.
- fluently
- Quickly and correctly, without counting on fingers.
- multiple of 10
- A number you say when counting by tens, like 30 or 80.
- equation
- A math sentence showing two sides with the same value.
- variable
- A letter, like n, that stands for an unknown number.
- fact family
- A group of related multiplication and division facts made from the same three numbers.
Ready to build your child’s confidence with linking 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 3 Unit 4 cover?
Illustrative Mathematics Grade 3 Unit 4 covers these math standards. Each one links to what it means, sample questions, and teaching strategies.
- 3.OA.A.3: Use multiplication and division within 100 to solve word problems.
- 3.OA.A.4: Find the missing number, like 7 × ? = 56 or ? ÷ 3 = 6.
- 3.OA.B.6: Use a times fact to divide: 32 ÷ 8 = 4 because 4 × 8 = 32.
- 3.OA.C.7: Know the times tables by heart, and divide within 100.
- 3.OA.D.8: Solve two-step word problems: add, subtract, multiply, or divide.
- 3.NBT.A.3: Multiply by multiples of 10, like 4 × 70 = 280.
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.