How to put fractions in order?

[joogle]

Say you have 3/8, 8/13, 2/9 and 21/11.

How do you put these in order, from smallest to largest? I'm looking for a shortcut.

[clock60]

Originally Posted by joogle

Say you have 3/8, 8/13, 2/9 and 21/11.

How do you put these in order, from smallest to largest? I'm looking for a shortcut.

i do not know the shortest way but i`d convert fraction into decimals all exept 21/11 it the largest without explanation
3/8=37+1/2
8/13=61+7/13
2/9=22+2/9
so 2/9 3/8 8/13 21/11 i even think that we can avoid fractional part of every number they do not play any serious

[bretania]

i think there must have been a typo here. if the last number is 21/11, the problem becomes too easy. probably the last num is 2/11 (instead of 21/11).

the usual way is to convert all of them into similar fractions (or fractions with same denominator).

But sometimes it takes time esp if your den are all primes.

so the other way is this.. again, i'm not sure if this will save time but maybe worth trying it out.


3/8, 8/13, 2/9 and 2/11

comp 3/8 and 8/13 first and eliminate the smaller nos if you're looking for the biggest number.

to com 3/8 and 8/13, just cross-multiply.
3(13) < 8(8) ---> so 8/13 is bigger.

Now, comp 8/13 and 2/9
8(9) > 13(2) ---> so 8/13 is still bigger.

now comp 8/13 and the last one 2/11
8(11) > 13(2) ---> still 8/13 is bigger.

therefore, 8/13 is the biggest in the group (granting of course that the last number in the problem is 2/11 and not 21/11).