All Zero Puzzle

Can you find correct numbers in some numbers? This is a puzzle game that delete all numbers of question. The rule is simple, but a difficulty increases step by step. ■Rule (1) There are "Question panels" on top of the screen. There are "Answer panels" on bottom of the screen. (2) You select an "Answer panel" and drop on a "Question Panel". Then number of "Question panel" changes. (before: Q=3, A=2 ---> 3-2=1 --> after: Q=1) (3) If all numbers of "Question panels" are zero (not minus), you clear the level. ■Feature ・All 200 level are free. ・The difficulty increases step by step. ・There is "Today's question". You can play a different game everyday. It is updated at 0:00(UTC+9). ・There is a support function. That is red panel which tells you possible of the correct panel. ・There is a support function. That is "undo" function. ・This game is a practice of "Addition" and "Subtraction". ・You can use a "Hint" function. ・There is a leaderboard (Game Center). ・There is not a time limit. You can think long time.