问题描述: 两道递等式计算,巧算 1个回答 分类:数学 2014-11-01 问题解答: 我来补答 7.8x7.5+7.8x2.6-78=7.8x7.5+7.8x2.6-7.8x10=7.8x(7.5+2.6-10)=7.8x0.1=0.78(6.2x6.8+1.8x6.8)x12.5=6.8x(6.2+1.8)x12.5=6.8x(8x12.5)=6.8x100=680 展开全文阅读