Percents Chapter 7 Section 7.5

Objective Students will work with percents and decimals

Concept The word percent means “hundredth” of “divided by 100.” The symbol % is used to represent percent

Concept Going from a decimal to percent, move the decimal 2 spots to the right, add percent sign Going from a percent to a decimal, move the decimal 2 spots to the left, remove percent sign

Write the percent as a fraction and decimal 29% 2.6% 637% 0.02% ¼% Example Write the percent as a fraction and decimal 29% 2.6% 637% 0.02% ¼%

Concept There are 2 methods that can be used to write a fraction as a percent. 1. divide numbers, move decimal 2. Use the following proportion a / b = x / 100

Write each number as a percent 3/5 1/3 4.7 Example Write each number as a percent 3/5 1/3 4.7

Concept In the next part of this section we will discuss solving percent problems. It is necessary to set up an equation or use a proportion to solve these problems.

Concept In percent problems, the word “of” means “multiply” and the word “is” means “equals” Or you may set up the problem in a proportion then cross multiply to solve is / of = % / 100

Example 15% of 180 is what number?

Example 23 is 25% of what number?

Example What percent of 64 is 48?

Concept When you solve an equation with decimal coefficients, you can multiply both sides of the equation by a power of 10 (10, 100, and so on) to get an equivalent equation with integral coefficients.

Example Solve 1.2x = 36 + 0.4x

Questions

Assignment Worksheet