## “Selfiest” Cities

Last week, I came across TIME’s ranking of the “selfiest” cities in the worldÂ and created the math task below.

Show the first slideâ€“”sharing learning intentions” and all that.

Display and discuss the selfies in Slides 2â€“8 to provide the context. Also, this will be helpful in the event that some don’t know what a selfie is. Hey, it happens. Each year I’d have to explain rock-paper-scissors to at least one of my Math 12 students (tree diagrams &Â experimental vs. theoretical probability &Â law of large numbers).

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Show the map belowÂ and ask students what the data might represent. Given theÂ previous discussion, I’m confident they’ll infer that each yellow dot represents one selfie taken in Anaheim. Yep, that’s Disneylandâ€“Las Vegas for kids!

Provide more details:Â each dot represents one Instagram photo taken during a 24-hour period tagged selfie that included geographic coordinates.

Put up this pictureâ€¦

â€¦which should lead to this question.

Hand out cards for Anaheim, Milan, and six other cities to pairs of students.

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Call on students to share and justify their rankings. Note that there is (probably) more than one possible ranking.

(Slide 19 is just a placeholder. SoÂ is Slide 30, 41, and 43. These signal the end of one part of the taskâ€“andÂ stopÂ me from clicking through to reveal too much too soon.)

Provide more information: the number ofÂ selfies and the number of selfie-takers. Have students writeÂ this information onÂ their cards.

Ask students to revisit their rankings.

Call on students to answer the questions above.