My son has been on school holiday for a month now and is keeping himself busy with numbers. It’s his latest thing and we’re running with it. He whispers sums in my ear, separates everything he owns into sets of 4s and 5s, and asks mathematical riddles of everyone he meets.
It’s compelling to watch his brain work, to see his intuitive sense of numbers at play. Stranger, though, are the gaps. Though he can add random numbers at will, and double any number up to 50, he remains stumped by ‘7 + 9’, which he’s convinced is 15. Luckily, such missteps are easily corrected and, best of all, he receives every clarification with delight, even euphoria.
There are transcendently lovely moments in parenting, brief and seldom but so glorious they catch you off guard. I simply didn’t expect fiddly sums to provide so many. Like when I taught him he could do superficially massive sums, like ‘4m + 6m’, because the solution is the same as for ‘4 + 6’, only with a million at the end. To watch him realise this was sublime; the cartoonish eye bulge, the exploding smile, the knowledge revealed of a tiny crack in the cosmos, a loophole so beautiful it seemed thrilling, possibly even illegal. He could add millions – actual millions – and he was walking on air.
Some questions I can’t answer to his satisfaction. I guess I learned adding and subtracting off-rote and have long since lost the ability to show my workings. Some of my calculations are hard to express, since they’re workarounds I developed when my brain was as wet and plastic as his. If I add 9 to 6, for example, a big part of my process involves knowing that 9 is 1 less than 10, so the resulting digit will end in a number that’s one less than 6. When I add, say, 24 to 37, I’ll subtract from the smaller number to get the larger number up to its nearest 10, and add what’s left. I do these things instantaneously, but reading back those descriptions makes them seem like the ravings of a maniac, chalked on some wall-length blackboard.
Try explaining negative numbers to a five-year-old. Scratch that: try explaining them to anyone. Within seconds you’ll sound like a hash casualty in a teenage bedroom, marvelling at the idea of imaginary numbers with practical uses. I try to sound confident as I tell him that, no, you cannot hold -4 apples in your hand, but they do still… exist. Somehow? He’s doubly confused when I tell him about infinity, but it’s as nothing compared to my own befuddlement as I try to explain it. I screw my face up like Robert Oppenheimer, as if contemplating the bleeding edge of quantum theory, and not the maths expected of a child who can’t yet tie his shoes.
If my son detects my internal crisis, he’s not letting on. He resumes his numerical onslaught and soon we’re adding millions together for what seems like hours. I look at the clock and it is 11am, with three weeks of summer holidays remaining. Lessons in infinity are, it turns out, everywhere.
Did Ye Hear Mammy Died? by Séamas O’Reilly is out now (Little, Brown, £16.99). Buy a copy from guardianbookshop at £14.78
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