Just to clarify I believe I read that at some point Arabic used to read numbers from least to greatest; i.e. one and ten and a hundred and a thousand. This is why the number is written left to right today. This pronunciation was later reversed except for the last two digits, in which it was preserved. Thus for example you read 1,125 today as: a thousand and one hundred and five and twenty (الف و مئة و خمسة و عشرين)