Ancient Device

Please note that this abacus uses Chinese system which is different from Japanese and Russian abacus.
If you have a hard time seeing the numbers, refer to this:

Spoiler: Numbers

→1999
+7428
-5360

-495
-186
+293

Here is the correct answer:

Spoiler: Solution

The answer: 3679

Refer to this for using the abacus:

@richardfu Oh that's true, sorry I didn't notice that.. the correct position for Chinese abaci are on upper position.

Great idea!!

@FREED0M So does this mean the level ought to be fixed re. the 3? Also, am I allowed to use a modern calculator and just feed the final number in, or am I suppose to compute the number using the abacus?

@Martin Magni yes I'm going to reupload the correct version of the abacus soon.

Actually players are meant to use the abacus to calculate... I know it's tedious but after trying by myself its actually more fun than I thought (although putting the number after calculating in a calculator still works)

Loved the idea of using an abacus as a maze!

@FREED0M Still waiting for fixed version. B.t.w., I suppose the end "beads" can't be moved right after being moved left? Won't that preclude using the abacus to calculate the answer?