It is a bit galling to be pulled up by a two and a half-year old but that is what happened to me the other week. There I was playing my Lord Chesterfield role sitting with the BoJ, going through some numbers with him, in the misguided belief that having a basic grasp of the decimal numeric system will stand him in good stead when he goes to school. Seeing the mental gymnastics that so-called students and graduates serving behind the bar of our local pub perform when called upon to subtract one number from another – I won’t go into their ability to then work out what coins of the realm make up the change from the proffered note –his grasp of some basic maths can’t come too soon.

Anyway, we were sitting going through a series of symbols representing quantity when we came to that tricky round one that represents nothingness. I ventured to suggest that it was a nought. ”No gandad”, quoth he – charmingly, the combination of g and r have so far eluded his pronunciation skills – “it is not nought, it is zero”.

Whilst admiring him for his precociousness, was he right?

It all comes down to the difference between digits and numerals. Under our Arabic numeric system – so much easier than the rather clunky Roman numbering system, I find – we have ten digits running from 0 through to 9. Any number we choose to represent is made up of a sequence of these digits and the sequence may consist of just one digit – as in 9 – or a series of digits – as in 1,674.

The problem is that we have conflated the nomenclature for digits and numbers. So the word two is used to signify both the digit two (which is a basic component of a whole series of numbers) and the number two which sits between the number one and three. This conflation applies to all the digits in the range 0 to 9 EXCEPT for the symbol for nothingness.

Nought – note the spelling, naught is an Americanism – is the name ascribed to the digit 0. The word zero describes the number 0. So if you are using it in the context of nothingness as in there are no sweets left, then it would be correct to call the symbol zero as it is being used as a numeric. However, if you were naming the component digits in a number – say 60, which, coincidentally we were – then the correct designation would be nought as the 0 is being used as a digit.

So there we are. Still, I admire his self-confidence and remind myself that the ability to distinguish between a digit and a number, particularly when 90% of the time we lazily conflate the nomenclature of the two into one, is probably beyond the grasp of even the apple of the eye of a doting gandad.