Go Math! Grade 4, Chapter 8: Multiply Fractions by Whole Numbers
In this unit, your child multiplies a fraction by a whole number. They start with unit fractions, seeing 5/4 as 5 × 1/4, then multiply other fractions, like 3 × 2/5, and write answers as mixed numbers. They solve story problems about recipes and distances. It follows adding fractions and leads into decimals.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
What is my child learning in Chapter 8?
- Seeing any fraction as a multiple of a unit fraction, like 5/4 = 5 × 1/4, and multiplying fractions by whole numbers in story problems. Learn more: Multiplying a fraction by a whole number
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 7 × 1/10?
- 7/70
- 1/70
- 7/10
How you can help
- Make a double batch of trail mix. If one batch needs 2/3 cup of nuts, ask your child how much two batches need, and show 4/3 cups as 1 1/3.
- Talk about reading time. If your child reads for 1/2 hour a day for 5 days, ask how many hours that is, and write it as 5/2 or 2 1/2.
- Line up 3 pencils that are each about 3/4 of a foot long. Ask how long the row is, as 9/4 or 2 1/4 feet.
Where kids can get stuck
- Multiplying the denominator by the whole number too, so 4 × 2/3 becomes 8/12.
- Writing 5 × 3/8 as 5 3/8, putting the numbers side by side instead of multiplying.
- Leaving 9/4 as the answer without seeing that it is more than 2.
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
- unit fraction
- A fraction with 1 as its numerator, like 1/4 or 1/8.
- multiple
- The product of a number and a whole number, like 6, 12, and 18 for the number 6.
- product
- The answer to a multiplication problem.
- mixed number
- A whole number and a fraction together, like 2 1/4.
- fraction greater than 1
- A fraction whose numerator is larger than its denominator, like 7/4.
- numerator
- The top number of a fraction, telling how many equal parts are counted.
- denominator
- The bottom number of a fraction, telling how many equal parts make one whole.
Want to help your child master fractions times whole 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.
Join the club
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 Go Math! Grade 4 Chapter 8 cover?
Go Math! Grade 4 Chapter 8 covers this math standard. Each one links to what it means, sample questions, and teaching strategies.
- 4.NF.B.4: Multiply a fraction by a whole number, like 2 × 3/4.
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.