How to calculate fractions

How to calculate fractions

The number made of a quantity of shares of unit in arithmetics, is called as fraction. It, as a rule, consists of two parts - numerator and a denominator. Each of them is an integer. In literal sense the denominator shows on how many parts divided unit, and numerator - how many from these parts took.

It is required to you

the manual on mathematics for 5 and the 6th classes

The sponsor of placement P&G Articles on the subject "How to Calculate Fractions" How to solve the equations with fractions How to transfer to decimal fraction How to solve fractions of the 5th class



It is accepted to divide common and decimal fractions acquaintance with which begins at high school. Now there is no such field of knowledge where this concept would not be applied. Even in the history we speak the first quarter of the 17th eyelid, and all understand at once that mean 1600-1625. Also often it is necessary to face elementary actions over fractions, and also their transformation from one look to another.


Reduction of fractions to a common denominator is, perhaps, the most important action over common fractions. It is a basis of carrying out all calculations. So, we will allow there are two fractions of a/b and with / d. Then, to reduce them to a common denominator, it is necessary to find a least common multiple (M) of numbers b and d, and further to increase numerator of the first fraction by (M/b), and numerator of the second on (M/d).


Comparison of fractions, one more important task. In order that to make it, reduce the set simple fractions to a common denominator and then compare numerators, whose numerator will appear more, that fraction and more.


To execute addition or subtraction of common fractions, it is necessary to reduce them to a common denominator, and after to make the necessary mathematical action with numerators of these fractions. The denominator remains without change. Let's allow it is necessary to subtract from a/b with / d. For this purpose it is required to find a least common multiple of the M numbers b and d, and after to subtract another from one numerator, without changing thus a denominator: (a * (M/b) - (with * (M/d)) / M


It is rather simple to increase one fraction by another, for this purpose it is necessary to multiply their numerators and denominators simply:
(a/b) * (with / d) = (a*c)/(b*d)

To divide one fraction into another, it is necessary to increase fraction of a dividend by fraction the return to a divider. (a/b) / (with / d) = (a*d)/(b*c)
To be necessary to remind that to receive the return fraction, it is necessary to trade numerator and a denominator places.


In order that from a common fraction to pass to decimal, it is necessary to divide numerator into a denominator. Thus the result can be both final number and infinite.

If from decimal fraction it is necessary to pass to ordinary, spread out your number on I kiss hour and fractional, presenting the last in the form of natural number divided into ten in the corresponding degree.