It was only the ‘dozens’ I ever sussed out, @Esspee. 12 pennies in a shilling, so 12 x fourpence would be be 4 shillings. And three farthings were 3/4 of a penny, so multiplied by twelve, 3/4 of a shilling, which = ninepence.
Phew!
I was pretty hopeless at maths in general - it took me 2 goes to pass O level, and still only got an E.
Good Morning Thursday 18th April 2024
Being quizzed by chemist's assistant in Boots.