依次排列的四个数,如果相邻的两个数的“差”都相等,那么,这样的四个数可以组成两道“和相等”的加法,或组成两道“差相等”的减法。例1:把10、20、30、40四个数填入各式的四个()里,使各个式子成立。①()+():()+()②()-()=()-()【分析与解】这道题目的特点是相邻两个数的“差”相等(10比20少10,20比30少10,30比40少10)。对于这道题目,解答思路分别如下:第1个式子把四个数搭配成“和相等”的两组。方法:最小数配最大数,另外两个数搭配。就 If the difference between the two adjacent numbers is equal, then the four numbers can form two “and equal” additions, or form two “difference” Equal “subtraction. Example 1: 10,20,30,40 four four-filled into the various types () Lane, so that each formula holds. ① () + (): () + () ② () - () = () - () [Analysis and Settlement] The problem of this topic is characterized by the ”difference“ of two adjacent numbers equal 20 less 10,20 less than 30 10,30 less than 40 10). The answer to this topic, respectively, is as follows: The first formula to the four numbers collocation ”and equal " two groups. Method: The minimum number with the maximum number of the other two with the number. on