a number puzzle with nine squares, each containing nine smaller squares, in which you have to put the numbers one to nine so that a number appears only once in each of the nine squares and in each row of nine across and down the puzzle 数独游戏(九个大方格中各有九个小方格,要求在空格中填数字一到九,且纵、横排各不重复) He passes the time doing sudokus. 他做数独游戏打发时间。 There are sudokus at four levels of difficulty. 有四个难度级别的数独。