Phoning New Friends

Sarah becomes close friends with five other soccer players at soccer camp. Upon returning home, Sarah speaks to each new friend for five minutes three times a week. Sarah's parents need to decide on a phone plan. Below are two phone plans that the parents are considering.

Flat Rate Cost per Minute
Low Rate Phone Plan $15.00 per month $0.15 per minute
Talk a Lot Phone Plan $30.00 per month $0.10 per minute

Sarah's parents want Sarah to determine which plan costs less because Sarah's parents want to spend as little as possible for all of Sarah's phone calls. Sarah decides to use the greater than, less than, equal to symbols on a paper to compare the plans. What could the paper show? Which plan should Sarah's family use? Show all of your mathematical thinking.

Instructional

More Accessible Version

Sarah becomes close friends with three other soccer players at soccer camp. Upon returning home, Sarah speaks to each new friend for five minutes three times a week. Sarah's parents need to decide on a phone plan. Below are two phone plans that the parents are considering.

Flat Rate Cost per Minute
Low Rate Phone Plan $15.00 per month $0.15 per minute
Talk a Lot Phone Plan $30.00 per month $0.10 per minute

Sarah's parents want Sarah to determine which plan costs less because Sarah's parents want to spend as little as possible for all of Sarah's phone calls. Sarah decides to write the greater than, less than, equal to symbols on paper to compare the plans. What could the paper show? Which plan should Sarah's family use? Show all of your mathematical thinking.

More Challenging Version

Sarah becomes close friends with ten other soccer players at soccer camp. Upon returning home, Sarah speaks to each new friend for five minutes three times a week. Sarah's parents need to decide on a phone plan. Below are two phone plans that the parents are considering.

Flat Rate Cost per Minute
Low Rate Phone Plan $15.00 per month $0.15 per minute
Talk a Lot Phone Plan $30.00 per month $0.10 per minute

Sarah's parents want Sarah to determine which plan costs less because Sarah's parents want to spend as little as possible for all of Sarah's phone calls. Sarah decides to write the greater than, less than, equal to symbols on paper to compare the plans. What could the paper show? Which plan should Sarah's family use? Show all of your mathematical thinking.

Plan

Underlying Mathematical Concepts

Possible Problem-Solving Strategies

Formal Mathematical Language and Symbolic Notation

A student may independently select a printed number line, number chart, ten frames, graph paper, etc. as they work on a task.

Possible Solutions

Solutions tabs

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