Two trains 200 miles apart are moving toward each other; each one is going at a speed of 50 miles per hour. A fly starting on the front of one of them flies back and forth between them at a rate of 75 miles per hour. It does this until the trains collide and crush the fly to death. What is the total distance the fly has flown? The fly actually hits each train an infinite number of times before it gets crushed, and one could solve the problem the hard way with pencil and paper by summing an infinite series of distances. The easy way is as follows: Since the trains are 200 miles apart and each train is going 50 miles an hour, it takes 2 hours for the trains to collide. Therefore the fly was flying for two hours. Since the fly was flying at a rate of 75 miles per hour, the fly must have flown 150 miles. That’s all there is to it.
When this problem was posed to John von Neumann, he immediately replied, “150 miles.”
“It is very strange,” said the poser, “but nearly everyone tries to sum the infinite series.”
“What do you mean, strange?” asked Von Neumann. “That’s how I did it!”
School classrooms can be exceedingly difficult places in which to learn mathematics well.
Teachers vary in passion and ability (as is natural); class behaviour and attitudes (and bullying) can alter the learning environment radically; learning in a large group at the same speed and with little opportunity to receive one-on-one help leads to boredom or frustration for many/most students; textbooks vary in quality and frequently lack stimulating material (because publishers restrict the size of the books); and sometimes students are negatively influenced by parents and peers who share their own bad experiences or attitudes.
Home educators, too, often feel that they lack sufficient understanding to teach their children mathematics … and the resources that they have access to can sometimes be bland, unstimulating, and even poorly explained or constructed.
My wife and I home educated our daughter and I have taught and tutored mathematics for many years. I am aware of the difficulties listed above and have often been asked by students and parents to create a website to share my understanding and resources with others. Crystal Clear Mathematics is the result.
Because this medium is not interactive (in the sense of allowing immediate interaction between you and me) I cannot provide the quality of tutition that I would like to offer you … but I hope you find the videos and the supporting files to be useful none-the-less.
This website and its associated FaceBook page and YouTube channel were all launched on Tuesday 20 November 2012.
Hi! I have received your message and checked this video. Your methods you mention for this video is brilliant! I am starting it now. … Thank you very much again for this video and I am hoping to watch more!
Shinyfio (on a CCM YouTube video about Using a Diary to Help Your Long Term Memory)
