Arithmetical calculations performed in the mind, without writing figures down or using a calculator.
- ‘Daniel Tammet is a man with an exceptional mind: he can perform mental arithmetic faster than a pocket calculator, and learn a new language fluently, even one as tortuously complex as Icelandic, in a matter of days.’
- ‘Lawrence Lee was known in the local area to be very good at mental arithmetic and it was this love of mathematics that he passed on to his daughter.’
- ‘Calling himself a mathemagician, he astonishes audiences with amazing feats of mental arithmetic.’
- ‘Kawashima's study compared the brain activity in hundreds of teenagers playing computer games and doing mental arithmetic.’
- ‘A market trader I met, who left school unable to spell ‘orange’, could do mental arithmetic with the speed of summer lightning.’
We take a look at several popular, though confusing, punctuation marks.