Tag Archives: rate

Introduction to Slope

which-jobSlope is one of the the most important topics in algebra and is often understood by students at a superficial level. I suggest introducing slope first by drawing upon prior knowledge and making the concept relevant (see photo above).  This includes presenting the topic using multiple representations: the original real life situation, rates (see photo above) and tables, visuals,  and hands on cutouts (see photos below).

10-dollars-per-hour-graphA key aspect of slope is that it represents a relationship between 2 variables. Color coding (red for hours, green for pay) can be used to highlight the 2 variables and how they interact –  see photo above and below.5-dollars-per-hour-graph

The photo below can be used either in initial instruction, especially for co-taught classes, or as an intervention for students who needs a more concrete representation of a rate (CRA). The clocks (representing hours) and bills can be left in the table for or cut out.cut-outs-hours-bills

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Starbucks would benefit from some math intervention

starbucks reward

Starbucks has changed their rewards program to “boost participation.” The chief strategy officer apparently could use some math intervention.

From USA Today (emphasis mine):

“Currently, customers with “gold” status have to visit 12 times to earn a free food or drink item. Under the new program, those customers will have to earn 125 stars to get a free reward.

Most customers spend around $5 with each visit, said Matt Ryan, global chief strategy officer. At that rate, a customer would still need to visit about 12.5 times, or spend a little more than $60, before earning a free reward.”

In other words, “most customers” will need to visit more often to get the same reward benefit.

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