How to subtract fractions with different denominators. To subtract fractions it is always easier to ensure that all the given fractions have a common denominator. Subtraction of fractions simply means taking away one fraction from another fraction. A fraction is a part of a whole.
How to subtract fractions with different denominators
To subtract fractions with different denominators, follow the simple steps below.
Step1: make the given fractions have a common denominator. Finding the LCM of the given fractions is the easiest way to find the common denominator.
Step2: After finding the common denominator of the given fractions. Add the numerators and take them over the common denominator.
Let’s look at the example below
\begin{aligned}&\text{Example 1: subtract }\space\frac{3}{7}-\frac{2}{5}-\frac{4}{35}\\
&Answer: \text{The LCM of 7,5, and 35 is 35}=\frac{(3×5)-(2×7)-(4×1)}{35}=\frac{15-14-4}{35}=-\frac{3}{35}\end{aligned}This is pretty, good right? Let’s look at another example
\begin{aligned}&\text{Example 2: Subtract }\space\frac{8}{5}-\frac{14}{15}\\
&Answer: \text{The LCM of 15 and 5 is 15.} =\frac{8}{5}-\frac{14}{15}=\frac{(8×3)-(14×1)}{15}=\frac{24-14}{15}=\frac{10}{15}=\frac{2}{3}\end{aligned}