“I am quite simply, numerically obtuse”

I came to a workable accommodation with my Arithmophobia the second I left school; “From this day forward,” I vowed, walking through the school gates for the last time, “I will never again, for as long as I live, put myself in a position where there’s even the tiniest chance that I might have to do mental arithmetic in front of people.

Cross my heart, hope to die.”

And, being the sort of person to take vows seriously — still honouring ‘till death do us part’ after nearly three decades; not sat in a ski lift since 1979; never touched tequila since 2002 — I’ve been as good as my word.