Multiply by a one-digit number
Multiplying a big number by a small one gives your child a quick way to answer real questions, like how many pages are in 4 books of 312 pages each. It leads to multiplying two two-digit numbers and dividing larger numbers this year, and in 5th grade to the stacked written method and multiplying decimals. And it shows up whenever an amount repeats: a weekly total over several weeks, or the cost of a few of the same thing.
In this video, your child will learn to multiply big numbers by a one-digit 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
23 × 3 = ?
Example 2
347 × 6 = ?
Your child's turn
1,236 × 4 = ?
The three key steps
- 1Split the big number by place.
- 2Multiply each part.
- 3Add the parts.
Mistakes to listen for
- Writing each digit’s product side by side, so 48 × 7 becomes 2,856 instead of 336.
- Losing track of the zero in a number like 3,045, multiplying the 3 as 300 and getting 2,760 instead of 24,360.
- Adding the leftover digits instead of multiplying them, so 427 × 6 becomes 2,400 + 27 = 2,427 instead of 2,562.
The lesson shows every step, so your child sees why it works. Read our parent's guide to multiplying large numbers by a one-digit 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 large numbers by a one-digit 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 large numbers by a one-digit 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 large numbers by a one-digit number
Questions at your child's level, about five minutes a day, on multiplying large numbers by a one-digit number and whatever PK-5 skills they need to develop. Unlimited practice, free forever.
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