Asinine math

Posted on September 6, 2016


That’s what the student is calling it.

I try to encourage a better attitude.

Welp, they’re figuring out the percent of the volume that balls take up in a cylinder… except that the radius of the balls is stuff like 0.02  … and then they add the condition hat you round to the fourth decimal place, which means throwing out a ton of data.   If you do as a *real person* would do (this is supposed to be like math in “real life”) you would change your units so you wouldn’t get 0.0001367  and numbers like that.   No!   We are to round that to 0.0001.   If you round stuff right, then your “calculated” percent is 50%.


The *text* makes a point of having students do two separate examples of balls in cylinders, and then have them compare and notice that hey! it’s the same!   So Student in Question didn’t do the rounding and got… 2/3 and thought, cool!  I know I’m right!   Connections made!

… and got the red box with the Incorrect! Try Again!

When they get “you’re wrong!” when you just didn’t round to what it said (ALEKS will tell you — hey, check your rounding)… I tell ’em hey, following directions is important.   Fine print is important.   However, tHis one …  how to justify.. at least he was here so I could confirm that yea, the correct relationship was 2/3… and agree with him that this was an example of “rounding error.”


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