For a while me and my class have been doing many things about fractions for maths.  Decimals, mixed fractions, improper fractions, etc…  I… I didn’t learn much due to my already extensive knowledge on fractions but it was a good refresher.  “The class” learnt a lot about fractions in equations.  It isn’t really complex if you have the right mindset or the right strategy when it comes to equations with fractions.  I’ll give a few examples of my learning.  5/10 – 4/10.  When it comes to like denominators (The bottom numbers of the fraction) and equations, I ignore the denominator because in the end, it won’t matter.  So, ignoring the denominator, you get 5-4 which equals 1.  add the denominator back and yippee, you have the answer, 1/10.

Another example is 1/2 – 1/3.  Now the denominators are unlike, when it comes to this I try to find the lowest common multiple (LCM) between the two denominators.  The LCM is the lowest multiple between your two numbers, don’t get it?  I’ll give an example.  Say… 5 and 3.  To find the LCM you’d list all the multiples you think you’d need.  Then find the lowest number that is in both “lists”.  In this case 3’s list is: 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36 (up to X12).  5 is: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120 (Also to X12).  The Lowest common multiple is 15 due to 15 being found the lowest on both lists.  Now back to the question, 1/2 – 1/3.

We find the LCM, no need for the list, its just six.  When encountered with an unlike denominator question the easiest thing for me is to just multiply the two denominators together, this doesn’t always work though.  So far, we have made things easier by making the two denominators, previously unlike, to become like.  So now the 1/2 – 1/3 is 1/6 – 1/6…  This doesn’t work though so lets continue.  Now, whatever you do with the denominator you’d do with the numerator (top number).  For the first fraction time we multiplied the 2 by 3 to get six.  Now we multiply the numerator, which is a one.  Now it is a 3.  Do the same with the other, that is a 2.  Now the fractions are 3/6 – 2/6.  We have successfully made the unlike denominators like. 🙂  Now finally the answer, is 1/6.

Hope you learnt something, if not, too bad.