Square-bashing

An army term for marching endlessly round and round a parade-ground. Generally applied to a tedious activity in which one is constrained to a limited set of activities, and in which the use of the mind is contra-indicated.


It was a 10p listing day on ebay yesterday. After half the morning spent in front of the laptop and the scales I had thirteen items entered into Turbo Lister, ready to go. Why is it such hard work? Why do I hate it so much? It should be easy enough. Identify your item, describe it, work out the weight and size and estimate a postage cost, and get a reasonable photo of it. And yet I had struggled, trying to force myself to carry on.

"Oi, you, pick those arms up! Press those arrow keys, left-right-left-right, up-down! On the command, choose category, now! Obtain the,( wait for it,) weight for it. Calculate postage, de-scribe, and, save. Right, let's do it again."

So there I was, thirteen items at 10p each, plus 3p for a gallery shot, so that was going to cost me thirteen times thirteen. I could have just clicked on start -> programs -> accessories -> calculator, but I was fed up with sitting in front of a keyboard and screen. It was slavery, and I became Spartacus and hit the button to send the laptop into standby mode.

I stood up and walked around outside, wondering how to work out what 13 times 13 was. I could remember twelve times twelve is 144, because I learnt the times-tables by rote, and somewhere in the back of my mind was a whisper that thirteen thirteens was 169, but how could I work that out without going through thirteen stages of mental addition? Was there an easy way to get to the answer if you knew the result of the square just before the one in question?

Here we go. Five fives are twenty five, and let's forget that we know that six sixes are thirty six. Twenty five plus a five is thirty, plus a six is - thirty six. OK, so let's forget that seven sevens are forty nine, and start from thirty six, add six to get forty two, and add seven to get - forty nine. Eight eights are therefore forty-nine plus a seven makes fifty six, plus an eight makes sixty four. See the pattern?

OK, back to the original question, and starting with twelve twelves make 144, add twelve to get 156, and add 13 to get 169. QED

Is there a point? I don't know, I just felt elated by the experience of working out yet another mental shortcut to cover for the maths I have forgotten. And not having to do algebra or delve into number theory to do it. And not having to ask Windows pretty-please to help you with the answer.

(Note for geeks, yes, I know there's a simple algebraic solution, but this is a blog, see? Algebra and quadratic equations belongs on the blackboard).