1. Class 7, September 24, 2015 Lessons 1.8 & 1.9

2.  By the end of this lesson, you should understand that: ◦ Percentages involve a numerator (comparison value) and a denominator (reference value)

3.  By the end of this lesson, you should be able to: ◦ Correctly identify the quantities involved in a verbal statement about percentages ◦ Convert between ratios and percentages ◦ Convert between the decimal representation of a number and a percent ◦ Read and use information presented in a two-way table

4.  Main idea: ◦ Every percent is really a statement about two quantities, specifically a comparison value and a reference value  Verbal descriptions of percents can be very difficult to understand without taking time to think carefully about the two quantities being compared. In general, when working with percentages, it is a good habit to ask what quantities are being compared.

5.  By the end of this lesson, you should understand: ◦ A percent has different uses, including being used to express the likelihood (or probability) of a certain event ◦ The importance of selecting the correct comparison value and reference value in calculating percentages

6.  By the end of this lesson, you should be able to: ◦ Extract relevant information from a table ◦ Select the appropriate values to calculate probabilities

7.  Main idea: ◦ Correctly identifying the comparison value and reference value is very important in calculating percentages  As with lesson 1.8, the key here is to be very careful with numerators and denominators when calculating percentages  Main idea: ◦ Percentages have multiple uses with different terminology, but the meaning is the same  The meaning of a percentage is always comparison to 100