Add within 100
Adding with confidence gives your child a solid base for almost all the math to come. Sums within 100 lead to adding within 1,000 later this year, then to multi-step problems, money, and time in 3rd grade. They also help your child notice when an answer is off, such as a total that is smaller than one of the numbers added. And it comes up everywhere: counting coins, totaling game scores, and adding up prices at the store.
In this video, your child will learn to add within one hundred.
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
34 + 25 = ?
Example 2
38 + 45 = ?
Your child's turn
57 + 36 = ?
The three key steps
- 1Start by adding the ones.
- 2Ten or more? Make a ten.
- 3Then the tens and the new ten.
Mistakes to listen for
- Forgetting the extra ten when the ones add up to more than 9, answering 75 instead of 85 for 47 + 38.
- Adding the tens and the ones separately but never putting the two answers together, so 47 + 38 stays as 70 and 15.
- Counting up one number at a time for every problem, which is slow and easy to lose track of, instead of jumping by tens.
The lesson shows every step, so your child sees why it works. Read our parent's guide to adding within 100 →
Is your child ready to practice what they've learned?
Bobby's Math Club offers unlimited practice for free.
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More 2nd 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 adding within 100, 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 adding within 100 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 adding within 100
Questions at your child's level, about five minutes a day, on adding within 100 and whatever PK-5 skills they need to develop. Unlimited practice, free forever.
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