Help the underground crystal mine by solving math puzzles. Fill the cars with the correct results. The app allows you to practice adding skills in a fun way. You can choose the difficulty of adding tasks up to 10, 20, or 100. Master adding to perfection! To fill the cart with the correct amount of crystals, press one of the three available answers displayed in the center of the screen. The number at the bottom of the screen is the result of adding the number in the upper left corner and one of the answers. Good luck!