Have students plan a trip itinerary trip using ratios and proportions to figure out a variety of common travel calculations. For instance, give the students the mileage between a specific starting point and end destination, and then give them a speed of transport to have them figure out how long it would take to get from Point A to Point B. Once they arrive at the simulated destination, have them plan day trips to take in a rented car, figuring in gas mileage and travel time. Another example would be to have the students calculate monetary conversions using currency exchange rates to figure out how much money they could spend on a shopping excursion.
Demonstrate the importance of ratios and proportions by taking the class down to the cafeteria for a baking exercise. You can apply the concepts to other cooking techniques as well, but baking typically requires high levels of precision measuring for a recipe to turn out correctly. Have the students figure out an accurate increase or reduction of a set recipe to provide exactly enough servings for a predetermined number of people. Explain how inaccurate calculations could lead to an inedible product or could lead to making too many treats, which would result in wasted food, time and money in a real-life business. Enjoy the treats you bake, or use them to have a bake sale fund-raiser.
A simulation of what life will be like in the real world can provide an entertaining way to demonstrate the importance of ratios and proportions. Give students some estimated living expenses, and then have them figure out how many hours they'll have to work in a part time job of their choice to be able to pay those bills.
Emphasize the value of understanding ratios and proportions by discussing a range of different careers that require these skills on a daily basis. Afterwards, have the students take a career test and determine how ratios and proportions apply to the job matches they receive. Take field trips to local businesses that use ratios and proportions on a daily basis, or invite the employees to speak to your class to give some specific examples about how ratios and proportions affect their respective areas of expertise. Some examples of industries that use ratios and proportions heavily could include those related to cooking and baking, as well as pharmaceuticals.