Add and subtract fractions with the same denominator
Once your child sees a fraction as a count of equal pieces, fraction arithmetic starts to make sense, and they avoid the common slip of adding tops and bottoms, which turns 1/4 + 1/4 into 2/8. It comes up in daily life, like adding 1 3/4 cups of flour to 1/2 cup. Next year they add fractions with different denominators, and later use fractions in measurement, science, and algebra.
In this video, your child will learn to add and subtract fractions with the same bottom 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
Omar eats 3/8 of a pizza. Leila eats 2/8 of it. How much do they eat in all?
Example 2
3 1/5 − 1 3/5 = ?
Your child's turn
Sana has 2 1/8 meters of ribbon. She uses 6/8 of a meter. How much is left?
The three key steps
- 1Add or subtract the tops
- 2Keep the bottom number
- 3Not enough parts? Split a whole
Mistakes to listen for
- Adding the denominators too, writing 5/12 + 6/12 = 11/24, an answer smaller than one of the starting fractions.
- Subtracting the smaller fraction from the larger, so 3 1/4 − 1 3/4 comes out as 2 2/4 instead of 1 2/4.
- Thinking a fraction can never be more than 1, so 7/4 looks like a mistake rather than one whole and three fourths.
The lesson shows every step, so your child sees why it works. Read our parent's guide to adding and subtracting fractions and mixed numbers →
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 adding and subtracting fractions and mixed numbers, 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 and subtracting fractions and mixed numbers 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 and subtracting fractions and mixed numbers
Questions at your child's level, about five minutes a day, on adding and subtracting fractions and mixed numbers and whatever PK-5 skills they need to develop. Unlimited practice, free forever.
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