I don’t believe I was unkind or thoughtless.
Apart from the factual answers I gave to the question I said this:
“Good grief, mk! “
(I was genuinely flabbergasted that an adult did not have the ability to perform these calculations. It was not unkind or thoughtless. It was a genuine expression of surprise).
“…this is not maths, it is simple arithmetic. “
(Just my view. I differentiate between what some call “maths” and what I call simple arithmetic).
“…it is rather like saying that the end of term play at the local primary school is theatrical drama.”
(again, just my view on equating maths with arithmetic)
“When I was at school we were taught (by our maths teacher) arithmetic, algebra, geometry, trigonometry, calculus, statistics etc. Yes, all maths. But if I were to ask a question about simultaneous equations I would head it "algebra". If I were to ask a question about the eight times table I would head it "arithmetic". “
(Same again, my take on the differentiation between maths and arithmetic).
I gave properly constructed answers to the question asked. I also expressed surprise at the inability of an adult in the UK to do the same. I’m not blaming the OP. I had actually compiled an answer which castigated the education system and highlighted the apparent discrepancy between the observation I made as a result of this question and the roaring successes in GCSE and ’A’ Level results of recent years. But I thought better of it. It prompted a bit of a debate (hence the 90-odd answers, when the question had been fully answered in about ten or so). We are continually told that the State education system in the UK is a rip-roaring success. It clearly is not. My only regret is that I did not make it clearer that I meant no criticism of mk. But I make no other apologies. It's a shame that one cannot make polite expressions of surprise without being labelled judgemental, unkind or thoughtless. Perhaps that's why the State education system is in such poor repair.
Now I'll take Mamyalynne's advice and retire gracefully from this.