1 2 3 = 1 1 2 3 4 5 6 = 1 1 2 3 4 5 6 7 = 1 填上加,减,乘,除,括号让算式等于1

问题描述:

1 2 3 = 1 1 2 3 4 5 6 = 1 1 2 3 4 5 6 7 = 1 填上加,减,乘,除,括号让算式等于1