# Do the Maths

I was writing out my morning pages the other day when I became aware that the pen I had been using to write for the past few weeks had begun to run out.

How many times, I wondered to myself, would the writing stretch around the globe when I eventually finished my task? It should be easy enough to calculate, if I could establish how much ink the average pen contained, and how long the line would stretch if it were drawn along the ground. Then I would have to establish the diameter of the earth and do some multiplication and some division – maybe even some adding up too, giving the fact that I was already on pen number two. It was nothing short of mathstastic.

I found Maths impossibly difficult at school. I worked really hard at it, but it remained a mystery never to be solved. I think it was probably because my approach to all learning was to commit everything to memory and so if the question I saw did not match one I had previously encountered, I was buggered.

Most of us would complain that the problem with the maths we were doing, was that we would never use it in real life.

‘When,’ we would ask, ‘are we ever going to use that in real life?’

Actually, quite a bit as it turns out, annoyingly.

Like when someone gives you a price which includes a GST levy of 10%, but you want the unit cost before tax and need to strip it off. Adding percentages is easy enough but taking them off needs algebra.

Or when you need to express an increase in numbers as a percentage. That’s so mathy it practically wears a pair of glasses and carries a calculator.

Or when you have a cake recipe that uses a 23 cm spring-form tin but you want to try baking it in a rectangular tin foil tray and you want to work out whether the tray will hold the batter for the cake. My understanding was that this calculation was going be be all about working out the comparative volumes of the two containers. The square one was OK, but the spring form-tin was round, which I was told was going to need PI, except that can’t be right because I want to cook cake, not pie.

In the end, I gave up trying to think about it and used a measuring jug of water to compare how much each container held. It got me the information I needed, but it did feel a little medieval. It is a fraught business, alright, but fortunately there is Google, which is pretty good at maths and can be used in a pinch. I guess you would expect that, given that it is named after a number.

I am now even sure why I started all this. Oh yeah, that’s right I wanted to work out the diameter of the earth. That will come in really handy for working out its volume later so that if anyone gets around to hollowing it out, we can use it as a giant flip-top rubbish bin. It turns out I have a load of useless stuff I can bung in there: the GST, a tinfoil cake tray, a pen which has now run out of ink, and the many, many hours I spent trying to crack maths.