If you are, like me, fascinated by this "old" tool called the abacus, or specifically the soroban, you've already managed to get your hands on a soroban and began to practice and learn how to add, subtract, multiply and divide with it.
If not, first, learn how to read a number on the soroban. Then, learn how to do the 4 basic operations by trying our virtual soroban, with step by step example of each operation. If you need more reference, try  and .
I have learned to use the soroban with the help of the very good book Le boulier, Initiation  by Jean Cumin and Jean Hossenlopp (published by Chiron in french). I have also read The Japanese abacus, Its use and theory , the book of Takashi Kojima.
Another recommended reading is the "Soroban" book produced and published by The Japan Chamber of Commerce and Industry and The League of Japan Abacus Association. You can download it freely on their site. It has been specially made by japanese for foreigners that want to learn the soroban.
A generator for exercices
The 2 books of Kojima and Cumin-Hossenlopp talk about the soroban examination   taking place in Japan for each grade, called kyu. They show examples of these examination and it's a good exercise to do these to practice and improve your soroban abilities.
So, I modified the little generator I already made for me to produce pdf files of these examination exercises and turn it into this website. You'll find below screenshots of how such documents look like. To see a real example, just go and try the generator.