智力问题,灵活开阔,且出其不意藏其不备,解决它常常不要模式,不倚重知识的深浅,平时想想做做,是一条磨炼智力的好途径。例1 把11枚硬币投入三只杯中,使每只杯中的硬币数为不同奇数,这个问题是不难办到的,但是,如果我们把硬币换成12枚,你还能办到吗? 对于11枚硬币,我们只要在三只杯子里分别放置1、3、7枚即可,对于12枚呢?显然,三个奇数的和是不会得到偶数的,要想加和是偶数,势必有的硬币能两次计数或不计数,顺此,就可能想到一只杯子套进另一只杯子的路子,从而一下子有同几种方法,比如第一只杯子放7枚, The intellectual problem is flexible and open, and it is not intended to be concealed. It is often not a model to solve it, nor does it rely on the depth of knowledge. Usually, thinking about it is a good way to temper intelligence. Example 1 It is not difficult to put 11 coins in three cups so that the number of coins in each cup is odd. However, if we replace the coins with 12, can you still do it? For 11 coins, we only need to place 1, 3, and 7 in each of the three cups. For the 12? Obviously, the sum of the three odd numbers is not even, and the sum is even. There are bound to be coins that can be counted twice or not, so along the way, it is possible to think of a way for a cup to fit in another cup, so that there are several ways at once, such as 7 in the first cup.