How to subtract fraction with different denominators

The main feature of the human mind is the ability to think abstractly. One of the highest forms of abstraction in the human world is the number. There are several categories of numbers, differing in properties. The most familiar and frequently used in everyday life are whole and real numbers. Usually numbers are written in decimal notation. Real numbers are indicated by decimal fractions. One of the drawbacks of recording decimals in decimal fractions is their limited accuracy. When accuracy is particularly important, numbers written as fractions (pair of the numerator-denominator). In some cases, the fraction is very convenient, but arithmetic with them is more complex than with decimal numbers. For example, to subtract fraction with different denominators, we need to perform several mathematical operations.

You will need

• Calculator or sheet of paper with a pen.

Instruction

1. Bring the fractions to a common denominator. Multiply the numerator and denominator of the first fraction by the denominator of the second. Multiply the numerator and denominator of the second fraction by the denominator of the first. For example, if the original fraction is equal to 6/7 and 5/11, what fraction, reduced to a common denominator will be equal 66/77 and 35/77. In this case, the numerator and denominator of the first fraction was multiplied by the number 11, and the numerator and denominator of the second fraction on the number 7.
2. Perform the subtraction of fractions. Subtract the numerator of the first fraction, the numerator of the second fraction. Record the resulting value as the numerator of the resulting fraction. As the denominator of the result of the substitute common denominator, obtained in the previous step. So, when we subtract fractions from fractions 66/77 values 35/77, will result 31/77 (from the numerator 66 was deducted from the numerator 35 and denominator by the same).
3. Perform a reduction of the fraction of the result, if necessary. Pick a greatest common divisor other than 1 for the numerator and denominator of the resulting fraction. Divided into the numerator and denominator. Write the new values in the numerator and denominator of the resulting fraction. The greatest common divisor other than 1 may not exist. In this case, leave as a result of the original roll.