How many km equals a mile, or how many miles equals a km? Struggling? It's little wonder that the maths skills of our children don't measure up in comparison with those in other countries.
Learning two systems is mind-boggling. But do children still need to know imperial measures? Of course they do, because as soon as they've left the classroom with metric mutterings still ringing in their ears, they step out into a disjointed and muddled world soaked in imperialisms.
For example, the local butcher has everything labelled in metric but everyone still asks for "half a pound of best mince please".
Builders pick and mix by telling me I'll need some "3m by 5inch"
floorboards, I see footballers dancing about in the six-yard box, we meet our friends for a pint and we're told that as a nation of fatties we're piling on the pounds. Sports commentators tell us in one breath that the marathon is "a gruelling 26.2 miles" yet in the next exhalation spit out "but first let's join Steve for the 100m".
Oh yes, and turn on the box after work and you're told that your perfectly good TV is rubbish and your world will be better viewed through a new 37in high-definition plasma screen. And while pound;2.19 for 3.6kg of Fairtrade bananas might be a bargain, what's 3.6kg in old money?
The petrol station tells me I'll be paying 93.7p a litre, but when I hit the road everywhere will be signposted in miles and that goes for the speed limit too.
It's the same when I go walking. The signs say miles but my Ordnance Survey map talks to me using the one km system.
But wait. We do like a good thriller and the mysteriously long metrication process is the Mousetrap of our time. Imperial measures might be murdered one day and I'll wager a couple of shillings on Reverend Green in the conservatory with a 30cm ruler. Seeing the light will probably dawn in the year 2020 when laser eye surgery will be available in all good butchers'
shops while you wait.
Anyway, my marking bag weighs a ton so I'm off to the pub for 568.26 millilitres of Guinness. But I'll probably just ask for a pint to be on the safe side.I haven't got an ounce of strength left to argue after this week.
John Dabell is a teacher trainer