Subtracting fractions with unlike denominators

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Subtraction is one of the basic arithmetic operations in math. Subtracting is finding the difference of the given numbers or quantities. Subtraction is denoted by the sign ‘-‘. In subtraction order of the number is important. Fraction is usually written in the “p/q” form. Here ‘p’ is the numerator and 'q' is the denominator. The denominator of a fraction cannot be equal to zero i.e. q not equal to zero. For Subtracting two fractions with different denominators the LCM needs to be calculated.

Example 1: Simplify and find the answer by subtracting the two fraction numbers 1/2 – 1/8?
Solution: Given is to find the difference of 1/2 – 1/6.
The fractions have unlike denominator. So the LCM of 2 and 8 = 8.
The fractions are written using the LCM = 1/2 – 1/8 = 4/8 – 1/8 = (4-1)/8 = 3/8.
Therefore, this gives difference of the fractions 1/2 – 1/8 = 3/8.
 
Question: Multiple choice question (Pick the correct option.)
What is the difference of subtracting the two fractions 3/4 – 1/3?
a)    7/12                b) 5/12            c) 1/12            d) None of these.
Correct answer: option b.
Given is to find the difference of the fractions: 3/4 - 1/3. Here both the fractions have unlike denominators.
The LCM of the denominators 3 and 4 is 12.
The denominators can be made alike by the LCM 12.
This gives, 3/4 – 1/3 = 9/12 - 4/12 = (9 – 4)/12 = 5/12.
Therefore, this gives subtracting the two fractions 3/4 - 1/3 = 5/12.
 

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