Answer:
Europeans had a perfectly fine way of doing computations that was every bit as good as Arabic numerals. They used a table and stones to do computations, similar to an abacus. Roman numerals were used to record numbers, not to do computations.
The abacus is an excellent computing device used in Europe and across Asia to China and Japan.
Even so, it took a couple hundred years more for Europeans to make the conversion. Computations aren't easier with Arabic numerals than with an abacus, and using them for computation requires paper for those computations, so there was a good reason not to use them. One minor advantage is that when you write down the computations, there's a record you can check.
Explanation:
