Many financial topics can be explored using algebraic concepts. Below we’ve highlighted one – cost-comparisons, but other areas, like banking and budgeting are also great for algebra classes.

Highlighted Problem: Texting 1, 2, 3

Kheri asked for the gift of a plan with unlimited texting.  She doesn’t know the details of their current plan, but she argued to her parents that with an unlimited plan they would be less stressed about how many texts she sends and they’d all save money.  Her parents thought it over, and then gave her a challenge:  if she can figure out the pricing of the current plan based on the last four monthly charges, they will upgrade to an unlimited plan.


In August, she sent 212 texts and the bill was 19.91. During September, the number of texts dropped to 163 and the bill was 18.79. October was a busy month, with 304 texts and a charge of 23.13. Finally, in November she sent 264 texts and it cost 21.73.

This is a nice problem to help students think about models companies use for pricing plans. It may be helpful in thinking about both what makes the most sense for Kheri and how to determine criteria to use when evaluating different plans from different carriers (or more generally when comparison shopping). It also is a great way to start a conversation about how some elements of particular products are very important to some users, while not relevant to others (for example, a high schooler may text his/her friends all the time, while the mother or father of a high schooler may not ever text!)

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