Consumer math represents the most immediate and practical response to the student mantra, “When am I ever going to use this?”
I was thinking about this yesterday during a late night run to Meijer to get some paper. They had two options: A ream of 500 sheets for $4, or a ream of 750 sheets for $5.80. Incidentally, I encourage my students and my son to always round the prices: Marketers want you to see “$3.99” and think “oh, it’s a little more than three dollars”. Stop falling for it! So, yes, the “actual” prices were $3.99 and $5.79, but we’re going to pretend that didn’t happen.
Anyway, I figured that the larger reams would be cheaper per sheet, but I did some quick math just to make sure. The way I did it at the time was to halve $4 to get a price per 250 sheets, then triple it to get $6 for 750 sheets, which is indeed more than $5.80, although frankly not enough to warrant the extra paper purchase for cost savings alone. I’m a teacher and use up far too much paper, so it’s worth it to me; besides, paper never really goes “bad”. But if that’s the cost saving on a food item, it’s worth thinking about whether it’s really worth it.
Since the paper is near the Skylanders figurines at Meijer, that also got me thinking about a game that Toys ‘R Us plays on its consumers. A Skylanders figurine might be $15 at Toys ‘R Us and $12 at GameStop. Why buy from Toys ‘R Us? Because they have BOGO40: Buy One, Get One 40% Off! Surely that means a savings, right?
Actually, 40% off a $15 item makes it $9. Add that to the $15 you pay for the first item, and it costs $24 for two… the same price as at GameStop.
So the most practical reason for learning math: Because the people who sell you stuff know math, and psychology, and will do what they can to get you to pay too much money, with a smile on your face.