Learn to calculate the percentage of the total that two given quantities represent to provide insight into diversity in groups of information. A percentage represents part of a whole. Usually, percentages are expressed as a portion of 100 percent, which equals the total. An example is a group of students consisting of 20 boys and 15 girls. Based on the total number of students, a percentage of the group is male while another percentage is female.

Add together the two numbers to get the total. For example, assume there are 45 men and 35 women in a movie theater. The total is 45 plus 35, which equals 80.

Divide each of the two starting numbers by the total. Call the results "X" and "Y," respectively. Round to two decimal places. Continuing the example, you have 45 divided by 80, or 0.56 for "X," and 35 divided by 80, or 0.44 for "Y."

Multiply the value of "X" and "Y" by 100 to obtain the percent share of the total for each group. Completing the example: 0.56 times 100 equals 56 percent, which is the percentage of the people in the movie theater who are men. Similarly, 0.44 times 100 equals a share of 44 percent of people who are women at the movie.