1. Ratios and Proportions Notes-Part 4

2. Benchmark Fractions

3. Benchmark Fractions
These are called benchmark fractions because they are easy to work with.

4. Completing Mental Calculations
How can we use benchmark fractions to calculate each percent problem?
25% of % of % of 364
75% of % of % of 364

5. Finding Percent of a Number-Bar Model
What is 40% of 250?

6. Finding Percent of a Number-Bar Model
What is 14 is 2/3 of what number?

7. Finding Percents-Bar Models
After eating at your favorite restaurant, you know that the bill before tax is $ and that the sales tax rate is 8%. You decide to leave a 20% tip for the waiter based on the pre-tax amount. How much should you leave for the waiter? How much will the total bill be, including tax and tip (tip before tax)? Show work to support your answers. Round if necessary.

8. Part of a Number-Cross Products
Cross multiplying proportions is a straightforward process that can be used to solve proportion problems. Cross multiply by multiplying a numerator by the other side’s denominator. Then, use algebra to solve for the unknown variable.

9. Cross-Multiplication
Find 20% of is 50% of what number?
Find 55% of is 5% of what number?