Family Plan
How much should you pay for a shared wireless plan?
Students will
- Use proportional reasoning to predict 30 days of cell phone usage based on 1, 7, and 15 days
- Calculate the monthly bill for two siblings on a family plan, including flat-rate items and overages
- Based on his/her usage, determine how much each sibling should pay
- Evaluate alternative wireless plans, and decide whether up- or downgrading would better fit their wireless behavior and save them money in the future
Before you begin
Students should be able to perform operations on decimals and apply the order of operations. The lesson applies unit rates and involves proportional reasoning, but extensive prior experience with these is not assumed. The focus in this lesson is more on constructing and communicating logical arguments than it is on sophisticated mathematics.Common Core Standards
Content Standards
Mathematical Practices
Downloads
Related Lessons
Civic Duty
Is it worth paying extra for a hybrid car? Students use proportional reasoning to determine how much hybrid owners save on gas, and how long it will take to make up the price difference.
On Your Mark
Do taller sprinters have an unfair advantage? Students use proportions to find out what would happen if Olympic races were organized by height.
New Twenty
How does life expectancy affect how you live your life? Students use proportions to determine what life expectancy must have been in the past in order for the phrase "30 is the new 20" to be accurate, and explore how life might change as life expectancy changes.
Need for Speed
How much does it cost to drive at different speeds? Students use unit rates and proportions to explore how a car's fuel economy changes as it drives faster and faster.
Licensed to Ill
Who should buy health insurance? Students use percents and expected value to explore the mathematics of health insurance from a variety of perspectives.
Letterboxing
How do aspect ratios affect what you see on TV? Students use ratios to explore why the image doesn't always fit on the screen, and examine how letterboxing might affect their favorite movies.
My Fellow Americans
Have presidential speeches gotten dumber? Students evaluate the Flesch-Kincaid formula with inputs from three different presidents and analyze the formula to predict how specific changes to a speech will impact its score.
Icy Hot (MS)
How have temperatures changed around the world? Students compare current temperatures to historical averages, and add and subtract positive and negative numbers to explore how the climate has changed in various cities over time.
Common Cents
How much is money worth? Students apply operations on rational and decimal numbers to calculate how much the U.S. Mint spends on different coins, and discuss whether we really need all these coins.
About Time
How has the pace of technology changed over time? Students create timelines of major technological milestones and calculate the time between major events using absolute value and operations on integers.
