Are there actually some systematic approaches to handle these cases? Or are there some libraries making this easier? We have so many places where we keep track of the offset and spread it over the items afterwards to mitigate this. It’s annoying as it’s most often a two step process and e.g. becomes even more complex when you have constrains on the numbers like applying discounts.
In this particular case, it's easier to think of the problem as "allocating $10 among 3 parties" rather than "dividing $10 among 3 parties." The latter insinuates equal distribution. Often, having the 3 parts sum back up to $10 is more important than giving an extra penny to one person and not dividing equally.
What I've used before is "Express the value in pennies. Divide by X (number of parties). Take the whole number part and give it to each person evenly. Take the modulus and distribute it one by one to each remaining party, until there is nothing left."
Example: allocate $10.01 among 3 parties:
1. You have 1001 pennies
2. Divide by 3 - give each person 333 pennies
3. Take the modulo 1001 % 3 - you have 2 pennies remaining. Time to distribute them round-robin!
4. Give one penny to person A. You have 1 penny remaining.
5. Give one penny to person B. You have no pennies remaining.
If you do this many times, randomly establish the order of the parties each time you round-robin them. In that case, no one will be systematically under-allocated, just because their name starts with the letter Z.
This is not a universal truth, and each situation is different. It may not apply to other kinds of money dividing situations.
