[求助]feifei section6-11

jasnoyang

11、S=m(m+4)(m+5) and m is a positive integer. Which of the following must be true?
(1) S is divisible by 3
(2) S is divisible by 4
(3) S is divisible by 6

看了feifei的解释还是不太明白，第3个选项是为何，能否请牛人解答一下，谢谢～

jasnoyang

啊，这下明白了，谢谢楼上解答！