# Section 6.8: Percent

## 6.8 Outline

1. Percent
2. Fractions/decimals/percents
1. procedure for changing a percent to a decimal
2. fraction/decimal/percent conversion chart
3. Estimation
1. unit fraction-conversion method
2. percentage
3. unit fraction comparison
4. The percent problem
1. the amount; percentage
2. percent; rate
3. whole quantity; base
4. procedure
5. warning: DO NOT ADD PERCENTS

## 6.8 Essential Ideas

PERCENT

Percent is the ratio of a given number to 100. This means that a percent is the numerator of a fraction whose denominator is 100.

To change from fractional form to decimal form:

Divide the numerator (top) by the denominator (bottom). Write as a terminating or as a repeating decimal (bar notation).

To change from fractional form to percent form:

First change the fraction to a decimal, and then move the decimal point two places to the right and affix a percent symbol.

To change from a terminating decimal form to fractional form:

Write the decimal without the decimal point, and multiply by the decimal name of the last digit (rightmost digit).

To change from a terminating decimal form to percent form:

Shift the decimal point two places to the right and affix a percent symbol.

To change from percent form to fractional form:

Write as a ratio to 100 and reduce the fraction. If the percent involves a decimal, first write the decimal in fractional form, and then multiply by 1/100. If the percent involves a fraction, delete the percent symbol and multiply by 1/100.

To change from percent form to decimal form:

Shift the decimal point two places to the left and delete the percent symbol. If the percent involves a fraction, first write the fraction as a decimal and then shift the decimal point.

The Percent Problem

A (this is the given amount) is P% (this is written as P/100) of W (this is the “whole quantity” and is follows the word “of”).

Here is the procedure to follow:

First, identify the percent; write it as a fraction P/100.

Next, identify the whole quantity; it is preceded by the word of.

Finally, the remaining quantity is the partial amount; it is the numerator of the second fraction in the proportion: P/100 = A/W.