When I was at school, I learnt many things. I learnt how to calculate the volume of a triangle using the lengths of its sides; I learnt what happened on Bloody Sunday in Russia; I learnt how to do long division by hand; I learnt how to make dove-tail joints, how to stand in the cold and get shouted at by the netball teacher, how to make speeches about Hinduism and how to draw bowls of fruit surrounded by candlesticks and artfully draped bits of silk. I also learnt - and this wasn't necessarily on the curriculum - how to make myself invisible, how to hide in the changing rooms during lunchtime and how to pretend that I couldn't hear a single word about me that anybody was saying.
The last set of skills have been useful - although finding changing rooms to hide in is more difficult as a teacher, and I often have to resort to the staff toilets - but the first set have not. Not once in my entire life have I ever used the wonders of trigonometry, despite being forced to study it week in and week out for five years. I have never needed to know how to draw a map that shows various geographic complexities, and I have never needed to divide seven figure numbers by five figure numbers in my head. There is no maths, in fact, that I need anymore that can't be done with my fingers or my mobile phone.
What they didn't think to teach me, however, in all of my GCSEs, in all of my A Levels, in my entire BA and an entire MA was: how to pump a bike tyre.
This piece of knowledge was lost, somewhere: presumably tucked away in the same place as how to unblock a shower or what gets rid of mould or how to check the oil in your car. Perhaps the teachers themselves didn't know either: perhaps their teachers didn't show them, and - like me - they're living in a muddled, confusing world of things they don't understand and can't admit to anyone for fear of admitting they don't actually know anything worth passing on.
One hour and fortyfive minutes. One hour fortyfive minutes, sitting on the kerb outside my house, fiddling with tiny little bolts and nuts (and - let's be honest - I don't actually know which one is a nut and which one is a bolt). One hour fortyfive minutes, talking to my bike.
"Why has this got a pointy stick coming out of it?"
Silence.
"Well, where on you is a hole that would fit a pointy stick?"
Silence.
"If I jab it in to the wheel, is that going to make matters worse?"
Silence.
"Is it a good idea to take this off?"
Bike lets out loud wheezing noise, as remaining air escapes.
"Okay, I guess not. What about if I just screw everything together, and then pump as hard as I can?"
Silence, punctuated by the sound of air coming out of the pump, and then - after I had squeezed the tyre and realised that there was absolutely nothing inside it - the sound of lots of swearing.
I'm considering buying a new bike; just wheeling this one into the river and getting another one. One with air in its tyres. This one lasted four weeks before the air came out: I could average out at another 12 bikes before I leave Japan, and never have to touch another bike pump again.
In the interests of economics, however, I've just had to make yet another embarrassing cry for help.
The Babacycle, I emailed as far and wide as I could, has two flat wheels and I don't know how to get air back in them. Can somebody come and save it from the river for me?
How are you still alive? a friend emailed back. Seriously. How have you got to 28 and are still alive? I'll be over later.
9 GCSEs, 3 A levels, a BA and an MA, and I know absolutely nothing of any use to anybody at all: least of all to me. Nothing at all. All I am is a silly girl with a blocked, mouldy shower and no oil in her car who can't pump up her own bloody bike tyres. I would have been better off staying at home throughout my teens, reading How To guides on the internet and working out how to hang my laundry so that it doesn't get peg marks in it or fall on the floor. Which is exactly what I'm going to be doing for the rest of this evening.
School, apparently, is very useful in teaching us the things that life will never bother asking from us: like revising as hard as you can for an exam and then finding out when you get in there that the pages that fell into the bathtub were the ones you needed to read. And I have the rest of my life to find out just how much else I missed while I was learning the periodic table by heart and sanding down the edges of a plastic clock I made that looked like a hummingbird but didn't actually work.
And - now that I am a teacher, even if temporarily - I can enjoy passing on yet more useless information that none of my students will ever actually use. And then I can also enjoy laughing at them in twenty years when they're all riding around on flat-wheeled bikes, smelling slightly.
Thank God for a thoroughly modern education.