28. Why do kids give stupid answers to simple maths questions?

Have a go at some of these: An athlete's best time to run a mile is 4 minutes and 10 seconds. How long would it take him to run 5 miles? It takes one orchestra one hour to play a symphony. How long would it take two orchestras to play a symphony? On a ship, there are 13 goats and 12 sheep. How old is the captain? Among schoolchildren, the most common answers to these questions are: 20 minutes and 50 seconds; half an hour; and 25 years old. Hence the title: where are these thoughtless, silly answers coming from? The bizarre and somewhat frightening thing is that this is a well-attested finding in many different countries and schools. School students predominantly seem to think that anything involving calculation, in the classroom at least, is a matter of doing a simple arithmetic operation on the numbers given, without any kind of sense-checking or thinking about the real situation behind the numbers.  This strange phenomenon demands explanation, not to mention fixing. In this episode, we look at several articles concerning this issue, why it's there, and what to do about it. Enjoy the episode.