Percents & Percent Change

$$\frac{a}{w}=\frac{p}{100}$$ where 'a' is the part, 'w' is the whole, and 'p' is the percent.

To find what number 'x' a percent 'p' of 'a' is, use the formula: $$x = \frac{a}{p} \times 100$$ .

Percent error is calculated as: $$\frac{|estimated - actual|}{actual} \times 100$$ .

To convert a percent to a decimal, divide by 100. For example, 35% = $$\frac{35}{100} = 0.35$$ .

Percent decrease is calculated as: $$\frac{original - new}{original} \times 100$$ .

Use the formula: $$x = \frac{12}{0.40} = 30$$ .

It means the new price is 80% of the original price.

To find the percent of a number, multiply the number by the percent (as a decimal). For example, 20% of 50 is $$50 \times 0.20 = 10$$ .

Percents are a way to express fractions with a denominator of 100.

Sale Price = Original Price - (Original Price x Discount Percent).