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Lesson 1: Factors and multiples

# Understanding factor pairs

Use multiplication and an understanding of area to identify factor pairs for 6 and 16. Created by Sal Khan.

## Want to join the conversation?

• Do you have to memorize the multipication table to get good at factor pairs?
• Yes, memorizing the multiplication table helps you get good at factor pairs. If you don’t have the multiplication table fully memorized, you can use strategies to help you with forgotten facts. Example: suppose you know that 7x7 is 49 but you forget 7x8. You can just add 49+7 to get 56.

There are also some tests you can use, to find factors.

If the last digit is 0, 2, 4, 6, or 8, then 2 is a factor.

If the digits add to a multiple of 3, then 3 is a factor.

If the last two digits form a multiple or 4, then 4 is a factor.

If the last digit is 0 or 5, then 5 is a factor.

If 2 and 3 are factors, then so is 6.

If the last three digits form a multiple of 8, then 8 is a factor.

If the digits add to a multiple of 9, then 9 is a factor.

If the last digit is 0, then 10 is a factor.

Have a blessed, wonderful day!
• Still do not understand factor pairs
• Factor pairs is just finding all possible pairs of numbers that when multiplied would equation the given number. Factor pairs of 16 are:
1 x 16
2 x 8
4 x 4
All 3 of these pairs multiply to 16.
Hope this helps.
• Video transcript

- What we're going to do in this video is talk about factors and factor pairs. Now when we talk about factors, these are really numbers that can be multiplied together to make some number. So, for example, if I were to talk about factors of six, I could multiply two times three to get six and so we would say that two and three are factors of six. In fact we would also say that two and three is a factor pair for six 'cause when I multiply those two I can get six. Now to think about all of the different factor pairs for a number we could think about it in terms of area. How can we make a rectangle with area six? Well you could do it if it's two units by three units. So it could look something like this, I'll just hand draw it. So let's say it has, so let's say our rectangle looks like this. So it has two rows and then three columns and lets say these all have equal area, it's hand drawn but you can see that the area here would be two times three, which would be equal to six square units. Now, what if, what are other
• How can I remember which is a Multiple and which is a Factor?
• a multiple is the answer (20 is a multiple of 5 times 4) 5 times 4 = 20
• can there be three factors in a factor pair?
• Well, they're called pairs...
It's easiest as a pair because if you know a factor of a number, you can just divide the number by the factor to get another factor.

Anyway, you could have a factor triplet if you broke one of the 2 factors in the pair into 2 smaller factors haha
This leads on to the idea of prime factorisation, which is quite interesting!
• Can I ask something is 1 a factor
• 1 is indeed a factor. In fact, it is a factor of every number! Why? Recall what a factor is: it's a number you can multiply by another number to get a certain result. You can multiply 1 by any number to get...well that very same number.
For ex:
1 * 5 = 5
1 * 100=100
1 * 123456789 = 123456789
This tells us that 1 is actually a factor of every number. "Every number" also includes negatives.
• yo can yall help me i dont know what a factor is
• a factor is 2 numbers multipy
• What is the defination of Factor and Factor pairs?
• Hello Dear!
A "Factor" is any number is any number that is multiplied by another number (Also a Factor) to get some resultant number (i.e. a Multiple of the two Factors).
Now, the two numbers that were multiplied collectively form a pair and are named as "Factor Pair".
I hope you would have got an understandable definition of the two.
Best regards.
• So cool At , at and at
• I don`t understand this at all