1. Lesson Topic: Problem- Solving Using Rates, Unit Rates, and Conversions Lesson Objective: I can…  Solve constant rate work problems by calculating and comparing unit rates

2. Let’s Review: Finding a common denominator

3. Example 1 - Fresh-Cut Grass  If I cut 3 lawns in 5 hours, what fraction of a lawn can I cut per hour?  If my friend cuts 5 lawns in 8 hours, what fraction of a lawn can she cut per hour?  How can we compare the two fractions?  Who is cutting lawns at a faster rate?  By how much?

4. Example 2 – Flying Fingers The secretary types 225 words in 3 minutes and the computer teacher types 105 words in 90 seconds.  What 2 rates can I pull out of this situation?  Who types at a faster rate?

5. Group Practice – Do With Your Row  If you’re a #1, you’re the timer for your group – Grab a stopwatch.  If you’re a #2 or a #3, you’re a walker. #2 will walk 2 laps and #3 will walk 3 laps. #2 goes first. Try to walk at a constant speed as we are doing constant rate work problems today.  Determine who walks at a faster rate by comparing the fractions of laps/seconds. When you’re done, #1 becomes #2, #2 becomes #3, and #3 becomes the timer.

6. Example 3 – Survival of the Fittest A cheetah runs 60 feet in 4 seconds and a gazelle runs 100 feet in 8 seconds.  What 2 fractions can I pull out of this situation?  Which runs faster?

7. Example 4 – Restaurant Advertising Darla delivers 350 menus in 2 hours and another employee, Drew, delivers 510 menus in 3 hours.  What 2 fractions can I pull out of this situation?  Who is faster?

8. Lesson Summary…  Constant rate problems always count or measure something happening per unit of time. The time is always in the denominator.  Sometimes the units of time in the denominators of two rates are not the same. One must be converted to the other before calculating the unit rate of each.  Dividing the numerator by the denominator calculates the unit rate; this number stays in the numerator. The number in the denominator of the equivalent fraction is always 1.

9. Evaluate Your Learning 4 3 2 1 How will you “Sharpen Your Saw”?