7th Grade Unit 4 Test Review

Front

What is the formula to convert a decimal to a percent?

Back

Multiply the decimal by 100 and add a percent sign. For example, 0.4 becomes 0.4 x 100 = 40%.

Front

How do you calculate percent change?

Back

Percent change = ((New Value - Old Value) / Old Value) x 100. For example, if the old value is 32 and the new value is 45, the percent change is ((45 - 32) / 32) x 100 = 40.6%.

Front

What is percent error?

Back

Percent error = (|Measured Value - Actual Value| / Actual Value) x 100. For example, if the measured value is 12 cm and the actual value is 14.25 cm, the percent error is (|12 - 14.25| / 14.25) x 100 = 15.79%.

Front

What is 40% of 230?

Back

40% of 230 is calculated as 0.4 x 230 = 92.

Front

What percent of 50 is 20?

Back

To find what percent 20 is of 50, use the formula (Part / Whole) x 100. So, (20 / 50) x 100 = 40%.

Front

Define 'percent' in mathematical terms.

Back

Percent means 'per hundred' and is a way to express a number as a fraction of 100.

Front

What is the relationship between fractions and percentages?

Back

A percentage is a fraction with a denominator of 100. For example, 25% is equivalent to 25/100.

Front

How do you find the whole when given a part and a percent?

Back

Use the formula Whole = Part / (Percent / 100). For example, if 20 is 40%, then Whole = 20 / (40 / 100) = 50.

Front

What is the formula for finding the part when given the whole and a percent?

Back

Part = Whole x (Percent / 100). For example, to find 40% of 230, Part = 230 x (40 / 100) = 92.

Front

Explain how to round a percentage to the nearest tenth.

Back

To round to the nearest tenth, look at the hundredths place. If it's 5 or more, round up; if it's less than 5, round down.