Thursday, October 30, 2014

Homework Hotline's dismal math.

  I wasn't feeling at all well today and so I stayed home. When I do this I invariably watch Homework Hotline on Mountain Lake Public Television. This is never a good idea because every time I have watched it the math teachers solving the math problems called in by students have tended to solve math problems using rote learning strategies devoid of any conceptual knowledge and completely separated from the real worldin which math problems occur.

Today, in the Halloween edition with the teachers dressed in costume, one of the math problems called in by one of the students was this. If a table is 1.75 meters long and 1 meter wide and a chair is 39 cms wide, how many chairs will fit around the table.

So, the math teacher, Sir Lancelot I think he was dressed as, solved the problem by  adding all the sides of the table together, then divided this total by the width of the chair. The total of the 4 sides was 5.5 meters. When he had divided 550cm by 39cm he got 14.1. Correctly ignoring the .1 he said 14 chairs will fit around the table

Although this answer is mathemtically correct it makes absolutely no sense in reality. To fit 14 chairs around the table you would have to fit 2 1/2 chairs at each end and 4 1/2 chairs along each side. The correct, realistic answer should be 12; 2 at each end and 4 along each side; a solution arrived at by dividing the width of a chair into the length of each side of the table. This would leave space between each chair and not require 2 of the chairs to be cut in half.

This is an example of why we, as a nation, struggle to teach math effectively. So often the math of the classroom, especially in middle and high schools, bears no relation to the math required in the real world.   

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