How to solve fractions 5th grade

In the 5th grade middle school introduces the concept of fractions. A fraction is a number consisting of a whole number of share units. Fractions are written in the form ±m/n, the number m is called the numerator, the number n of its denominator.
If the module of the denominator is greater the numerator of the module, such as 3/4, the fraction is called proper, otherwise improper. A fraction may contain the integer part, for example 5 * (2/3).
To fractions, you can apply different arithmetic.

Instruction

1. Bringing to a common denominator.
   
   I suppose that fractions a/b and c/d.
   
   - First and foremost is the number of knock(least common multiple) for the denominators of the fractions.
   
   - The numerator and denominator of the first fraction is multiplied by the NOC/b
   
   - The numerator and denominator of the second fraction is multiplied by the NOC/d
   
   An example is shown in the figure.
   
   To compare fractions, they must lead to a common denominator, then compare the numerators. For example, 3/4 < 4/5, see figure.
2. Addition and subtraction of fractions.
   
   To find the sum of the two fractions need to be brought to a common denominator, then put the numerators, leaving the denominator unchanged. Example of addition of fractions 1/2 and 1/3 are shown in Fig.
   
   The difference of the fractions is the same way, after finding a common denominator, the numerators of the fractions are subtracted, see the example in the figure.
3. Multiplication and division of fractions.
   
   When multiplying fractions, the numerators and denominators are multiplied together.
   
   In order to divide two fractions, you need to roll back the second fraction, i.e. to change its numerator and denominator reversed, and then multiplying the obtained fractions.