Adding and Subtracting Fractions
Let’s go over the basics of how to add and subtract fractions. There are two different types of fractions that we usually encounter when we add or subtract them.
The first one, which is the Like Fractions, is easy because the bottom numbers (denominator) are alike. While the second one, Unlike Fractions, have different denominators. Thus, the process in adding or subtracting these types of fractions is different.
In Like Fractions, adding and subtracting them is easy, because you don’t need to do anything aside from adding or subtracting the upper number (nominator) while retaining (not doing anything for the bottom numbers (denominator). Please see the example below,
½ + ½ = 2/2
¾ + ¼ = 4/4
In contrast to Like Fractions, the only way to add them without doing division is to change them without changing its value. In order to do that, we need to find something called the least common denominator (LCD) -it’s really just the LCM of our denominators. Once you have the LCD, multiply it to each of the fraction so they both have the same denominators. Please see the example below:
= ½ + ⅛
LCD = 8 (Find out how we got the LCD, please click on this link)
8(½) = 4/8
8(⅛) = ⅛
½ + ⅛ = 4/8 + ⅛
4/8 + ⅛ = 5/8
Video by mathantics