1,3,9 and 27 are magic numbers! Their sum is 40 = 1 + 3 + 9 + 27. The other fact is you can derive any number between 1 to 40 using this number once and addition/subtraction operations. Example ... 5 = 9 - 3 - 1 31 = 27 + 3 + 1 It will be like studying and playing at the same time! The number is displayed on board, you have to tap on proper numbers (1,3,9,27) to derive that number and then tap on 'Check'. Timer is running so play this game fast! If you are correct, next number is displayed. If they are incorrect, game is over! Try again. Now you can update your score in Game Center. You can update LeaderBoard with Points!2 Modes!1Numbers in sequential manner. 2Numbers in random manner.