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
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%.