The local artists have a shop/gallery in the town centre, at present closed because of Coronavirus. I sometimes go there and one of the things I buy is greetings
cards. I like
Alan Morley's
cards, and often buy £10 worth. The first ime I did that, whoever was behind the counter confidently told me my £10 worth of cards would cost £12.50, and got fat‑finger and rang in about £12500000.00, which fortunately the till didn't believe.
The next time I went there, it was somebody different who did some arithmetic on his phone, which told him my cards cost £20.
The third attempt was a bit more successful; the old gent said he was a retired engineer, so he ought to be able to get the arithmetic right. I said, “I thought engineers' aeithmetic went, ‘It's more than £9.50 and under £10.50 on my slide rule; shall we just call that a tenner?’”