This App "81 numbers ascend memory" is a game to look for numbers from 1 to 81 in ascending order. There are 9 numbers on nine stages. After the first touch at each stage, tiles of answer are hidden. This is a game to memorize the position of the number.
Touch from 1 to 81. So you recognize the course order of the touch by short time and memorize it at a moment and you touch them in order quickly.