3的倍數=>3,9,15,21,27
2的倍數=>2,4,6,8,10,12,14,16,18,20,22,24,26,28,30
剩餘=>1,5,7,11,13,17,19.23,25,29
第五張為13
3.故有30張分別標示1~30號的紙牌。先將號碼數為3的倍數的紙牌拿掉,然後從剩..-阿摩線上測驗