任意4个数加减乘除求24，类似扑克牌的求24游戏的算法-Arbitrary number of addition and subtraction multiplication and division 4 for 24, similar to playing cards for 24 games of the algorithm

有一分数序列：2/1，3/2，5/3，8/5，13/8，21/13...求出这个数列的 前20项之和。 1.程序分析：请抓住分子与分母的变化规律。 -There is a score sequence: 2/1, 3/2, 5/3, 8/5, 13/821/13 ... find the number of columns and the top 20. 1 program analysis: Please seize the variation of the numerator