It was my birthday a few weeks ago! Why yes, I had a very nice birthday, thank you for asking. My sister took the train in, and we went out to lunch and then got dessert at my favorite coffee shop. It was over my steaming mug of tea and chocolate-covered pretzel that she presented me with a beautifully wrapped gift.
I thought at that moment I had everything I needed in life to be happy (notably, a steaming mug of tea and a chocolate-covered pretzel). But my sister knew, in a way only sisters can, there was a void in my life.
A void exactly the size of one (1) math clock:
Naturally, I got very excited about this present. Perhaps a little too excited, because as I gazed at it in rapture, I immediately noted that I had few mathematical quibbles with the clock.
In the 7 o’clock place is the equation 52 – x2 + x = 10. However, this equation actually has two solutions: 7 and -6. (You can tell this by factoring: -x2 + x + 42 = 0; x2 – x – 42 = 0; (x+6)(x-7) = 0; so x + 6 = 0 which means x = -6; and x-7 =0 which means x = 7).
Of course, because the equation is on a clock, we can assume the solution x must be 1 < x < 12, which means we can discard the -6. But sometimes it’s fun to be just a bit persnickety.
My other issue is the equation in the 9 o’clock position, which is 3(π-.14). First of all, for the love of math, PLEASE put a zero in front of the decimal point. It’s just considered good form, as it draws the eye to the decimal and ensures it will be noticed no matter what: bad handwriting, a misplaced erasure, or a lazy clock-reader.
But there’s a bigger issue here. As the folks at Wikipedia summed up so nicely, “π is an irrational number…its decimal representation never ends or repeat”. In other words, π does not equal 3.14, it equals 3.141593…and many many more decimal spaces. So the equation in the 9 o’clock space does not equal 9, it equals 9.004779… o’clock. So you’ll be running 17.2 seconds late for that 9 o’clock appointment if you go by this clock. (Since 0.004779 hours * 60 min/hr * 60 sec/min = 17.2 seconds)
Needless to say – or maybe it needs to be said now – I love this clock. My critique was merely a way to luxuriate gloriously in a hearty math debate, the way sports fans dissect their beloved team’s game the next morning. However, after I finished my running commentary it occurred to me I was being a bit rude. Nothing like giving someone a gift and have them point out with joy all the flaws it has!
However, a glance at my sister’s face showed she had taken no offense. Maybe it was my obvious passion and love for both math and this math clock that put the smile on her face.
Or maybe she had no idea what I was saying, and had zoned out to her happy place.
In either event, thanks for the great gift! I am one math clock richer, and a very lucky woman.