Interactive tutorial on percentages using an applet. A percentage is used to express part of a whole using a special fraction with denominator equal to 100. So for example the fraction 27 / 100 is denoted using percentage as 27%, where % is the percent sign. Also the percentage 33% can be written as a fraction 33 / 100. Compared to fractions, percentages are easy to compare.
click on the button above "click here to start" and MAXIMIZE the window obtained.
Use the top slider to change the percentage of colored squares. The ratio of the number of red squares to the total number of squares, which is 100, is the percentage. Note that a percentage may also be written as a fraction or a decimal number. These are also displayed on the right side of the applet.
Use the the slider to model 25%. What is the fraction corresponding to 25%? What is the decimal number corresponding to 25%?
Use the the slider to model 50%. What is the fraction corresponding to 50%? What is the decimal number corresponding to 50%?
The easy way to rewrite a percentage as a decimal number is to divide the percentage by 100. For example 30% is equal to 30 / 100 = 0.3. Use pencil and paper and calculate the decimal numbers corresponding to these percentages: 23%, 57% and 100%. Use the applet to check your answers.
To find a fraction corresponding to a given percentage, you change the percentage into a fraction and reduce if necessary. 50% is equal to 50 / 100. Divide the numerator and denominator by 50 to obtain 1 / 2. Use pencil and paper to find the fractions corresponding to the percentages: 25%, 33%, 40%, 75% and 90%. Use the applet to check your answers.