I have a backend system for restaurants & food services. On the front end people are using a huge variety of measure units for recipes and such (kilo, cup, gallon, pint, small spoon, big spoon, pinch of salt, dash of pepper and so on). But i need to convert all that to something small and indivisible to make calculations, reports and analytics and the backend. However, to show some info and reports to the user i have to convert all the stuff backwards to the 'user-friendly' measure units.
Thus it can lead to errors in numbers (round-off errors and such).
What is the best practice to deal with that? Thank you!