Percent Change and Percent Error

Front

What is Percent Change?

Back

Percent Change is a way to express how much a quantity has increased or decreased relative to its original value, calculated as: \( \frac{(new value - old value)}{old value} \times 100 \)

Front

What is Percent Error?

Back

Percent Error measures the accuracy of an estimate compared to the actual value, calculated as: \( \frac{|estimated value - actual value|}{actual value} \times 100 \)

Front

How do you convert a percentage to a decimal?

Back

To convert a percentage to a decimal, divide the percentage by 100. For example, 35% as a decimal is 0.35.

Front

What is the formula for calculating Percent Change?

Back

The formula for Percent Change is: \( \frac{(new value - old value)}{old value} \times 100 \)

Front

If a price decreases from $50 to $30, what is the percent change?

Back

Percent Change = \( \frac{(30 - 50)}{50} \times 100 = -40\% \) (a decrease of 40%)

Front

What is the percent proportion formula?

Back

The percent proportion formula is: \( \frac{a}{w} = \frac{p}{100} \) where 'a' is the part, 'w' is the whole, and 'p' is the percent.

Front

If you estimate a score of 40 points and the actual score is 30 points, what is the percent error?

Back

Percent Error = \( \frac{|40 - 30|}{30} \times 100 = 33.33\% \)

Front

What does a percent change of 0% indicate?

Back

A percent change of 0% indicates that there has been no change in value.

Front

How do you find the percent of change when the new value is less than the old value?

Back

When the new value is less than the old value, the percent change will be negative, indicating a decrease.

Front

What is the percent change if a product's price increases from $20 to $25?

Back

Percent Change = \( \frac{(25 - 20)}{20} \times 100 = 25\% \) (an increase of 25%)