How do you Subtract Fractions
Most students have a problem with subtracting fractions as the rules are not known by them and they get confused with fractions. However, if the rules are understood, subtraction of fractions is extremely easy. This is useful in daily life as well as fractions are needed in almost all spheres of life – from cooking and measuring of ingredients, to carpentry, architecture, and designing and even by farmers for growing crops.
Subtracting fractions is easy if the following steps are followed. In order to subtract fractions:
a) The bottom numbers which are known as the denominators should be the same.
b) The top numbers which are known as the numerators should be subtracted. The answer then needs to be put on the denominator
c) The fractions then need to be simplified
Further breaking up the steps in subtracting fractions the fractions should be built such that the denominators of both are equal. When the fractions are subtracted, it is a must for the denominators to be equal. This can be done by finding the common denominator. This is accomplished by finding the Least Common Denominator. The fraction then needs to be built to an equivalent fraction.
The equivalent fraction then needs to be rewritten using the least common denominator which now becomes the new denominator. Then the numerators can be subtracted, keeping the equivalent fraction denominators. After the answer is obtained, the fraction can be reduced or simplified further if need be.
If mixed numbers need to be subtracted, they need to first be converted to improper fractions which mean fractions which have larger numerators than the denominators. The least common multiple needs to be found and then they need to be subtracted like ordinary fractions.
The further breakdown of this is :
a) The mixed numbers need to be converted to fractions by multiplying the denominator using the whole number and then it should be added to the numerator. The yield is considered as the new numerator. The original denominator is then to be used. For example, if the number is 1 5/8 it can be written as 13/8.
b) Suppose from this number you are subtracting 2 ¾ then this too needs to be converted, and it will yield 11/4.
c) In both these fractions, 8 is the least common multiple, and so the fraction 11/4 is to be multiplied by 2 so as to arrive at 8 as the denominator for both the fractions. This will yield the answer 22/8 (when 11/4 is multiplied by 2).
d) The original number 13/8 should be used to subtract 22/8 which will yield -9/8.
e) This can be converted to a mixed fraction and will yield -1 1/8. This is easier to read and to comprehend as well.
When fractions need to be subtracted from a whole number, the whole number should be converted into a fraction. For example 7 – 4/5 can be converted to 7/1 – 4/5 and then the same rules of subtraction of fractions need to be followed.