Understand volume
Volume is the third kind of measuring your child meets, after length and area, and keeping the three straight will help them for years. Knowing that volume counts cubes filling a space is what makes the length × width × height formula later this year make sense. It also answers everyday questions like how much a box, a fish tank, or a bag of soil will hold.
In this video, your child will learn to understand volume with cubes.
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 box is 4 units long, 2 units wide and 1 unit tall. Volume = ? cubic units
Example 2
A box is 3 units long, 2 units wide and 2 units tall. Volume = ? cubic units
Your child's turn
A box is 3 units long, 3 units wide and 2 units tall. Volume = ? cubic units
The three key steps
- 1A unit cube is one cubic unit.
- 2Fill it: no gaps, no overlaps.
- 3Count them: that's the volume.
Mistakes to listen for
- Confusing volume with area, counting the squares on one face of a box instead of the cubes inside.
- Ignoring gaps and overlaps, estimating a box's volume by tossing in cubes loosely and counting them.
- Assuming the taller container always holds more, when a short, wide box can hold more than a tall, narrow one.
The lesson shows every step, so your child sees why it works. Read our parent's guide to volume: how much space is inside a solid →
Is your child ready to practice what they've learned?
Bobby's Math Club offers unlimited practice for free.
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More 5th grade Measurement & Data, 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 volume: how much space is inside a solid, 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 volume: how much space is inside a solid 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 volume: how much space is inside a solid
Questions at your child's level, about five minutes a day, on volume: how much space is inside a solid and whatever PK-5 skills they need to develop. Unlimited practice, free forever.
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