mm * dd * yy = YYYY

mm * dd * yy = YYYY

Oh, the mental games you can play... If you like little mathematical challenges, you might enjoy this.

Earlier this century (wow, I think that's the first time I've ever uttered that phrase!), I would sometimes amuse myself by seeing what number turned up if you multiplied the 3 parts of the date together (ie, if today were 6/10/04, its number would be 6*10*4=240). The numbers could range anywhere from 0 (any day in 2000) to 36828 (12*31*99). It occurred to me that at some point the number would be the same as the 4-digit year. That is, mm*dd*yy=YYYY.

One night after reading to my daughter, Shaina, I mentioned this to her and wondered what the first day this century would be where this was the case. We thought about it for a while. "Could it be this year? Could it be next year?" As we thought about it we realized different constraints were falling into place, making the search easier. We actually arrived at the answer without using a pencil and paper.

So what is the first day this century when mm*dd*yy=YYYY?