# Highest common factor

Discussion in 'Personal' started by Doglover, Apr 6, 2011.

1. ### Doglover

My daughter has to work out the highest common factor of 50 and 125.
She has to do little diagrams breaking down the 50 and then 125.
So we get - 50 = 2 x 5 squared and 125 = 5 cubed.
The next stage is confusing us.
According what she has been shown the HCF = 2 x 5 squared, but that equals 50 :/
Help?

2. ### bombaysapphireStar commenter

The HCF is the factors which they share which is just 5 squared = 25.

3. ### ResourceFinder

50 = 2 x 2 x 5 x 5

125 = 5 x 5 x 5

Look for what they have in COMMON

5 x 5

So HCF = 25

4. ### ResourceFinder

oops ... just ignore the extra 2

50 = 2 x 5 x 5
The rest was ok though

5. ### Doglover

Ahh, I think I see now......

6. ### Doglover

So - 98 and 147
The HCF = 2
I think I misinterpreted what she was told to do, and I mean you couldn't expect her to remember what she was told

7. ### ResourceFinder

no

98 = 2 x 7 x 7

147 = 3 x 7 x 7

In COMMON

7 x 7

HCF = 49

8. ### doomzebraOccasional commenter

The highest common factor of 50 and 125 is 25
(what is the highest common number by which both 50 and 125 can be divided to give a whole number)

9. ### Doglover

Oops I did that wrong!

10. ### Lilyofthefield

What's the biggest number that goes into them both, innit?
*Disclaimer: I is **** at Maths.

11. ### ResourceFinder

Yes, but Doglover's daughter needs a method for finding HCF

12. ### doomzebraOccasional commenter

doan go dissin yesself Miss Lily, you 'as mad maths skills

13. ### anon3372

That is how I do Maths.
No system. But I get there. Eventually.

14. ### anon3372

But Lily and me don't get the method.

15. ### anon3372

RF - do you remember a very long thread with me?
You very patiently explained...I must have driven you potty.
I do Maths my way - which is invarioubly the long way round, but it makes sense to me.
And I get the right answers.
But it drove my Maths teacher mad.
I got a B O level.
So somehow, my skitty methods work.

16. ### ResourceFinder

But Doglover and her daughter will

17. ### Doglover

Yep, but she has been taught a specific method which she has to use, which is what is confusing us.
I know what factors are, lol, but it's the method and the little tree like diagrams which are confusing :s
She had to use a similar method to find the lowest common multiple too.

18. ### ResourceFinder

I do not recall it but I am sure you did not drive me potty ... I can usually take a couple of approaches and hopefully get there

A good move if, as you say, the answer is correct

19. ### Doglover

Sorry crossposted RF

Tee hee....

Sowwy.