常题多解,饶有趣味,趣题多解,更是余味无穷,今举一例,供同学们共赏。求证:任取六个整数排成三列,每列两个;则至少有两列数字(共四个)之和为偶数。从初一到高三的同学,都能解答此题。请同学们先各自独立解答,再参看下列五种证法。一题到手,一般人的习惯是采用直接证法。 There are many solutions to the questions, interesting, interesting questions, and endless flavors. This is an example for the students to enjoy. Proof: Any six integers are arranged in three columns, two in each column; the sum of at least two columns of numbers (four in total) is even. Students from grade one to grade three can answer this question. Ask the students to independently answer each other, and then refer to the following five kinds of evidence. In the first question, the habit of the average person is to use direct evidence.