This how-to video explains about how to add fractions with uncommon denominators.
To add fractions with uncommon denominators three steps are involved:
1)Find the lowest common denominator
2)Covert to the higher equivalent fractions
3)Add and reduce
Let's see this with an example, 3/4 + 5/6, first we have to find the lowest common denominator, to do this take the multiples of both the denominator, the multiples of 6 are 6,12,18.... and multiples of 4 are 4,8,12,16...., look for the common integer in both the multiples, here the common number is 12, hence 12 is the lowest common denominator.
Then convert to the equivalent fractions, this will give
9/12+10/12 i.e., 3*3/12 + 5*2/12.
Now add and reduce, 9+10/12 which is 19/12= 1 7/12, this can be further reduced to mixed numbers when needed.
Hence the steps given in the video is very helpful to find fractions with uncommon denominators.