Subtract multiples of 10
Subtracting tens lets your child stretch the facts they already know to much bigger numbers: 7 tens take away 3 tens leaves 4 tens, in the same way that 7 - 3 = 4. It is a step toward 2nd grade problems like 74 - 38, where children think about tens and ones separately and sometimes break a ten apart. Without this idea, subtracting larger numbers can feel like a pile of unrelated steps.
In this video, your child will learn to subtract multiples of ten.
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
40 − 10 = ?
Example 2
50 − 30 = ?
Your child's turn
60 − 50 = ?
The three key steps
- 1If there are no ones, write a zero.
- 2Then take away the tens.
- 3Count the tens that are left by tens.
Mistakes to listen for
- Forgetting the zero, writing 4 instead of 40 as the answer to 70 - 30.
- Counting back by ones from 70, thirty separate times, instead of counting back by tens: 60, 50, 40.
- Answering 1 instead of 10 for 60 - 50, losing track of the fact that the answer is still in tens.
The lesson shows every step, so your child sees why it works. Read our parent's guide to subtracting tens, like 70 - 30 →
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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 subtracting tens, like 70 - 30, 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 subtracting tens, like 70 - 30 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 subtracting tens, like 70 - 30
Questions at your child's level, about five minutes a day, on subtracting tens, like 70 - 30 and whatever PK-5 skills they need to develop. Unlimited practice, free forever.
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