Addition and subtraction of fractions become similar to the same actions over integers when fractions have identical denominators. Therefore, first of all, fractions are required to be reduced to a common denominator. For commission of operations of division and multiplication of fractions it is not required to reduce fractions to a common denominator.
Instruction
1. If you need to increase at each other fractions, you should multiply separately all numerators and separately all denominators.
2. If you need to divide one fraction into another, trade places numerator and a denominator of a divider (fraction into which the first fraction is divided), and then make operation of multiplication of the received fractions (see Paragraph 1).
3. In case you need to put or subtract fractions, you need to learn for a start whether they have identical denominators. If this is so, then the procedure of addition or subtraction represents subtraction or additions of numerators of fractions, and the denominator remains the same. For example, 4/5-2/5=2/5.
4. To read or put fractions with different denominators, it is necessary to reduce them to a common denominator. As a common denominator the common multiple of denominators of initial fractions undertakes. It is the simplest to find it by multiplication of denominators of fractions. Make it.
5. Domnozhte numerator of each fraction on denominators of all other fractions.
6. Now subtract or put the numbers received in numerators, and you will attribute the common denominator received in Paragraph 4.