摘要
1 A dozen(12个)Ping-Pong balls are num-bered from 1 to 12.Tom separated the balls into twogroups and noticed that the sum of the numbers onthe balls in the first group equaled the sum of thenumbers on the balls in the second group.What isthe common sum(依次求这两组乒乓球上的数字和)?有12个乒乓球,每个乒乓球上分别标有从1到12的一个数字.汤姆把这些乒乓球分成两组,发现两组乒乓球上的数字和相等,求这两组乒乓球上的数字和是多少?
