ABSTRACT
When thinking about using mathematics in everyday life, money is the first domain that most people think of. Control of your finances has always been an important ingredient in human happiness. It is also worth being more sophisticated than Mr. Micawber's advice to David Copperfield, in the context of Victorian England:
Annual income 20 pounds, annual expenditure 19 pounds, nineteen and six, result happiness. Annual income 20 pounds, annual expenditure 20 pounds ought and six, result misery.
Charles Dickens (1850). David Copperfield, Chapter 12