The round multi-colored invaders returned again and you had an important mission - to destroy them in the game Orbiting Numbers Subtraction. But the previous ones are no longer suitable for the method, the enemy has rebuilt and you need to do the same. In the middle of the field is the circle in which the subtraction example is located. Solve it and find the ball with the corresponding result. After finding, click on it and thereby you destroy the alien spaceship. Act quickly, which means you have to solve puzzles at a fast pace, which is very useful for the mind.