How to solve problems with percent

The percentage is a decimal fraction, hundredth of a whole number, which is taken as one. The percentage is denoted in mathematics the sign "%", which is derived from the word cento, a hundred. There is also a version that the percent sign was the result of a typo and is subsequently firmly established in mathematics. Task interest and application of percentage in various calculations are very important, because the use of percentage and calculating percentage wide. Mathematical operations with percentages are used in the economy, when calculating inflation, rising stock prices and the definition of purchasing power. But everyday life the percentage is very common and is used in calculating the family budget, calculating Bank interest and interest on loans.

Instruction

1. Solve problems involving percentages simple enough, but there are certain rules. One percent is defined as a hundredth part of the number. For example, 1% is 0.01, and 5%=0,05 etc.
   
   When solving problems on percentages, you must determine the percentage of the number example could be the calculation of 20% of 450. To solve this problem, there are two ways: 20% *0,45=90 or 450*20/100=90
2. For solving problems of interest can be identified several ways:
   
   1. the percentage number is calculated by multiplying the number by the percent written as a decimal fraction;
   
   2. the percentage of one number from another is computed by dividing the first number by the second, and the fraction is written in the form of interest;
   
   3. the percentage of two numbers is determined by the formula: a/b*100%.