Most people that use a microwave oven are not aware that they are using a bizarre numbering system. In the microwave oven world, the mathematics work like this:
50 = 50 90 = 90 100 = 60 120 = 80 200 = 120On the left is what you would key into the machine, and on the right is the number of seconds the microwave will run. If you type 98, you get 98 seconds, if you type 99 you get 99 seconds, but if you add just one more and type 100, then you only get 60 seconds. This is completely nonsensical when you think about it, yet most people seem to accept it without a second thought.