Subtraction of three digit numbers online pirate game. In this game students in the following grades are going to improve their knowledge on this basic math skill: 3rd grade, 4th grade, 5th grade, 6th grade and 7th grade. Subtracting large numbers will involve regrouping in some instances. That simply means borrowing numbers across places and adding them while on those places. Subtraction of three digit numbers follows the same principle of subtracting two digit numbers. The only catch here is paying attention to the fact that some numbers have to be borrowed. The current game is a free online math game. It is a video game involving two pirates. It can be played as a group game or an individual practice game. Have fun learning.