All school Mathematics stores have a wealth of teaching aids lying around. Looking through our cupboards I came across this box titled “Box of Cards”. It was produced in 1991 by Edward Kadocka & Craig Irons.
None of the games in the enclosed booklet made me want to use them in my classes. So I wondered what else I could use the contents for. The cards enclosed were sturdy and colorful. There were 4 different rectangles and 2 different triangles. I removed 2 of each rectangle (pictured below) and wondered how many different rectangles could be made using one or more rectangles? The picture shows one solution (8 x 7) using all 8 cards.
This involved a systematic investigation. I employed the help of my colleagues, who were soon enjoying the challenge of a new Mathematics investigation. I produced a worksheet and tried it out on my year 7’s. They mostly engaged with it, and it fitted in perfectly with the area unit we were studying.
I would be interested to hear from anyone who tries “How Many Rectangles?” and also to see if you agree with our solutions!