Working behind a bar taught me more about maths than school ever did

I hated maths at school. The mere thought of the next class would fill me with dread; my books were filled not with equations or graphs, but doodles and drawings (flowers, horses, the usual). I feigned headaches just for a 10-minute reprieve while I went to the bathroom.

Somehow, I scraped a “C” grade in my GCSEs, but the relief I felt after taking my final class, knowing I would never again have to pretend I knew or cared about tree diagrams or circle theorems, was borderline euphoric.

It wasn’t until one of my first jobs, working evening and weekend shifts at a local pub in my north London hometown, that I discovered any kind of aptitude or interest in equations.

This was your classic old-boy boozer, with a patterned carpet that still smelled strongly of cigarette smoke, numerous sticky tables and a tired arcade machine bleeping wearily from the corner. The landlord hosted a weekly poker night for the ragtag bunch of regulars that included an ex-heavyweight boxing champion and a guy known as “Tottenham John”, who was the only one allowed a bar tab.

I loved working there. Everyone called me “Rosie” – it was the one place I never got harassed by creeps because the landlord and his mates would have thrown the guy out (not necessarily in one piece) in three seconds flat.

My parents were a bit alarmed, especially when the landlord called up and asked, in his low growl, if I was free for a shift that evening. But it was great, not least because it taught me more about maths than those painful classes at school ever did.

The rickety old till wasn’t up to much, which meant it was on me to tot up the cost of a round, and work out how much change to give back.

After a few weeks I could do this in an instant, even factoring in the discounts applied to regulars for whom a pint of Whitbread Best Bitter cost the same as it had five years ago, never mind the cost of inflation.

I knew the exact angle to tilt a pint of Guinness while pouring and the amount of time needed to let it settle. I could calculate the volume flow rate of beer into a pint glass so I knew how many seconds I could turn my back before I needed to return to it.

Later, at university, working at a local pub in Swansea involved a different kind of maths. Like how many pints it takes before a student throws up over the table (ideally you figure that out before serving them any more).

And how many hours of sleep I’d get if my shift finished at 11pm and I had to be in my first lecture by 9am, factoring in the hour it took to clean up then walk home. This was maths, only it was the kind of stuff I’d never been taught at school. It was infinitely more useful.

Rishi Sunak is promoting maths all wrong, and you might be surprised to know that it runs parallel to his attacks on so-called “soft” subjects, such as music and art. His obsession with pushing the more “serious” maths and sciences inevitably makes them sound boring and soulless – why would 16-year-olds care about helping the UK economy?

It’s the same nonsense that me and my classmates were peddled all those years ago: “You need to learn algebra,” the desperate teacher would tell us. “But why?” we howled. We still don’t know the answer.

The prime minister should change the curriculum to make maths a more practical subject. Kids should be calculating the number of subscriptions they need to cancel in order to save up for a mortgage. Or the distance in miles vs kilometres they need to travel outside of central London in order to find something affordable.

Test their aptitude for percentages by showing them examples of the gender pay gap for FTSE 100 directors (then see what percentage of girls in the class still want to work in an industry where those female directors earn, on average, 74 per cent less than their male peers). How much of it adds up?