Find factor pairs
Knowing how a number breaks into factors gives your child a real feel for how numbers are built. This year it helps them see why 2/3 and 8/12 are equal: multiply 2 and 3 by the same factor, 4, and you get 8 and 12. Next year, finding a common denominator for 1/4 and 1/6 means finding a shared multiple, 12. And at home, factors are how you share snacks evenly or set out chairs in equal rows.
In this video, your child will learn to find all factor pairs of a 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
Factor pairs of 6: how many?
Example 2
Which number is a factor of 21?
Your child's turn
Which is a factor pair of 18?
The three key steps
- 1Try 1 row, 2 rows, 3 rows …
- 2None left over? A pair.
- 3Fewer in a row than rows? Stop.
Mistakes to listen for
- Missing factor pairs, such as finding 2 × 18 and 3 × 12 for 36 but not 4 × 9 or 6 × 6.
- Mixing up factors and multiples, saying 12 is a factor of 3 when they mean it is a multiple of 3.
- Leaving out 1 and the number itself, so the factors of 15 are listed as only 3 and 5.
The lesson shows every step, so your child sees why it works. Read our parent's guide to finding factors and multiples up to 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 4th grade Problem Solving, 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 finding factors and multiples up to 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 finding factors and multiples up to 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 finding factors and multiples up to 100
Questions at your child's level, about five minutes a day, on finding factors and multiples up to 100 and whatever PK-5 skills they need to develop. Unlimited practice, free forever.
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