Modular Arithmetic




Dido's Problem



Smart Joe

Fuzzy Logic



I can still clearly recall the day Smart Joe joined our class. It was on the first day of school after Christmas break. Everyone was crowding around the new kid full of awe. He had a watch and he could even tell the time! The teacher disturbed our conversation and made us take our seats. Luckily the only free seat was next to mine, so Smart Joe sat down next to me. He told me all kinds of fascinating stuff, but the real hit came on the next day during math.

We had been assigned some problems and I was trying to count on my fingers properly, when I noticed that Smart Joe just took a look at his watch and wrote down the answer. I asked him about his trick after school. His answer was so brilliant and easy I still can't understand why the teacher didn't teach math in his way. He counted on his watch instead of his fingers, which of course makes it much faster.

This is why: if you have the problem 5 + 3 and you use your fingers, you first have to count off five fingers, then three fingers, and in the end you have to count how many fingers you have total. If you use the face of a watch however, you just have to go to the five, go three numbers further, and voila, you see right away that it adds up to eight. For subtracting you just go counterclockwise. If you have the problem 9-2 you go to the nine, take two steps back, and you see it's seven. Much easier!


Test it yourself and solve the following probelms on Smart Joe's watch!

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