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How would you work out 1/5 of something if you knew 3/5??

For example, say 3/5 of the number of males in a school is 36. how would you work out 5/5 e.g how do you work out 1/5 first???
http://www.helpingwithmath.com/printables/images_fractions/Fifth03.png

so you know what the 3 green bits are worth all together. how could you find just one of the green bits ?
Original post by Bertybassett
For example, say 3/5 of the number of males in a school is 36. how would you work out 5/5 e.g how do you work out 1/5 first???


If you know 3/5 of a number and you wanna work out 1/5, simply divide the answer you got for 3/5 by 3.

To make things clearer, 3/5 of 60 is 36. You can either divide 60 by 5 to give 12 or divide 36 by 3 to give 12.

Hope this helps :smile:

Posted from TSR Mobile
If you know 3/5 of something, divide by 3 to work out what 1/5 would be.
3/5 = 3 lots of 1/5. (3 * 1/5)
Divide 36 (3/5) by 3 to get 1/5.
answer is 12, meaning 1/5 = 12.
then just multiply 12 by 5 to get 5/5, or 2 to get 2/5 etc.
divide by 3? so, 12.

12x1 = 12
12x2 = 24
12x3 = 36
12x4 = 48
12x5 = 60

5/5 is 60
1/5 is 12.

If you're still confused reply and I'll help try explain (though you should remember I'm not the best math teacher in the world :lol:)

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