I would like to know any easier method to compare fractions. If I have 3 fractions, I can easily compare them by cross-multiplying. However, if I have like the following, what's the easiest way to compare?
Sort the following from least to greatest
9/17 3/13 2/3 3/16 19/20 5/7 2/9 7/15
The only way I currently know of is to compare 9/17 to all fractions then compare 3/13 to rest of the fractions and so on..This is very time consuming.
3/16 is less than 4/16 which is 1/4 so 3/16 is about .18 or so.
2/9 is less than 3/9 which is 1/3. 2/9 (doing long division .22)
3/13 is less than 3/12 but greater than 3/15 so its inbetween .25 and .2
7/15 is a little less than half.
9/17 is a little more than half
2/3 is .666667
5/7 is a little more than 2/3
19/20 is obviously the greatest.
U gotta know values of key fractions.
1/6 1/4 1/3 1/2 2/3 3/4 4/3 5/4.
Also aproximating helps here: by doing aproximation u can at least organize certain fractions in some places for example:
3/16, 2/9 , 3/13 in least group. 7/15, 9/17, 2/3 ,5/7 in middle group
and lastly 19/20 as the obvious greatest # in the group.
From here u can again do some aproximations or long division to find out certain values.
Just from the first split into 3 groups, u can probably elimante some answer choices and then only have to figure out the decimal value of a few fractions.