Multiply a fraction by a whole number
This is your child's first step into multiplying with fractions, and it ties fractions back to the multiplication they already know. It shows up in the kitchen, such as tripling a recipe that needs 3/4 cup of milk. In 5th grade, they multiply a fraction by a fraction, like 1/2 × 3/4, and learn why multiplying by a number less than 1 gives a smaller answer.
In this video, your child will learn to multiply a fraction by a whole number.
The lesson stops at each question for your child's answer.
Three problems, each a little harder
Each problem is worked step by step. Your child will solve the last one before Bobby shows how.
Example 1
A snail crawls 1/8 of a meter each minute. How far does it crawl in 3 minutes?
Example 2
3 × 2/5 = ?
Your child's turn
A puppy eats 2/3 of a cup of food at each meal. How much food does it eat in 4 meals?
The three key steps
- 1Multiply the top
- 2Keep the bottom number
- 33 thirds or 5 fifths = 1 whole
Mistakes to listen for
- Multiplying both the top and bottom by the whole number, so 2 × 3/4 becomes 6/8, which still equals 3/4.
- Getting the right fraction without a sense of its size, leaving 15/8 unrecognized as almost 2, or 1 7/8.
- Adding 5 and 3/8 in a word problem that calls for 5 groups of 3/8.
The lesson shows every step, so your child sees why it works. Read our parent's guide to multiplying a fraction by a whole number →
Is your child ready to practice what they've learned?
Bobby's Math Club offers unlimited practice for free.
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More 4th grade Numbers & Place Value, with questions your child answers along the way.
Questions parents ask
Does my child need an account to watch?
No. You can watch this on any device at any time. If your child would like to practice multiplying a fraction by a whole number, and you'd like parent-friendly reports on your child's progress and growth, you can join Bobby's Math Club for unlimited free practice.
What happens when my child answers a question?
A right answer gets a cheer, and the lesson carries on. If your child isn't sure, they can tap "I don't know yet", and Bobby gives the answer and shows another example. Nothing is scored or stored.
Is this the same lesson that's on YouTube?
Yes. Here, the lesson stops at each question and waits for your child to answer. On YouTube, each question stays on screen for a few seconds, and then the lesson plays on.
Where can I learn more?
There's a short, kid-friendly lesson like this one for every Pre-K to 5th grade math skill, all in our video library. Our parent's guide to multiplying a fraction by a whole number has more on where kids get stuck and how you can help at home. In the club, your child practices at just the right level, about five minutes a day, and you get parent-friendly reports as they grow. Learn more about how it works →
Practice multiplying a fraction by a whole number
Questions at your child's level, about five minutes a day, on multiplying a fraction by a whole number and whatever PK-5 skills they need to develop. Unlimited practice, free forever.
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