Into Math Grade 5, Unit 5: Decimals: Multiplication and Division
In this unit, your child multiplies and divides decimals to the hundredths. They start with patterns: multiplying or dividing by 10, 100, and 1,000 moves each digit to a new place. Then they use models, place value, and estimates to multiply and divide decimals and to place the decimal point with confidence. It follows decimal addition and subtraction and leads into geometry and data.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
What is my child learning in Unit 5?
- Explaining why multiplying or dividing by 10, 100, or 1,000 shifts each digit, and using exponents to write powers of 10. Learn more: Multiplying and dividing by 10, 100, and 1,000
- Multiplying and dividing decimals to the hundredths, using area models, place value, and estimates to place the decimal point. Learn more about adding and subtracting decimals to hundredths: Adding and subtracting decimals to hundredths · Learn more about multiplying decimals to hundredths · Learn more about dividing decimals to hundredths
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
Amara's family packs rice for a food bank in bags of 1.5 kilograms. How many kilograms of rice are in 10 bags?
- 0.15 kilograms
- 15 kilograms
- 11.5 kilograms
How you can help
- Use money to show powers of 10: ten dimes make $1, and a hundred pennies make $1. Ask what 10 × $0.35 is and what $4.50 ÷ 10 is.
- Figure out a total at the store, like 3 pounds of apples at $1.49 a pound. Estimate first, then multiply together and compare.
- Split a cost evenly, like $7.50 shared by 3 people, or a 2.4-mile trail walked in 4 equal parts. Ask how much each share or part is.
Where kids can get stuck
- Using the 'add a zero' shortcut on decimals, so 4.2 × 10 becomes 4.20 instead of 42.
- Moving the decimal point the wrong way when dividing, so 6.5 ÷ 10 becomes 65 instead of 0.65.
- Placing the decimal point by habit, so 0.4 × 0.2 gets written as 0.8 instead of 0.08.
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
- power of 10
- A number like 10, 100 (10 × 10), or 1,000 (10 × 10 × 10), made only of 10s multiplied together.
- exponent
- A small raised number that tells how many 10s to multiply together, as in 10³ = 10 × 10 × 10.
- decimal point
- The dot that separates the whole number from the parts of a whole.
- tenth
- One of 10 equal parts of a whole, written 0.1.
- hundredth
- One of 100 equal parts of a whole, written 0.01.
- product
- The answer to a multiplication problem.
- quotient
- The answer to a division problem.
- estimate
- A close guess found by rounding or using easy numbers.
Want to help your child master multiplying and dividing decimals?
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 Into Math Grade 5 Unit 5 cover?
Into Math Grade 5 Unit 5 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.