递等式计算(能简便则简)3.4*6.5/6.5*3.45.7*5?
递等式计算(能简便则简)3.4*6.5/6.5*3.4 5.7*5.7+5.7*7.5-5.7*3.2 37.78-19.59+41.32-30.41 2/1.25-1.25/2
解:(3.4×6.5/6.5)×3.4=11.56 5.7×5.7+5.7×7.5-5.7×3.2=5.7×(5.7+7.5-3.2)=5.7×10=57. 37.78-19.59+41.32-30.41=37.78+41.32-(19.59+30.41)=79.1-50=29.1 `2/1.25-1.25/2=(2×2-1.25×1.25)/(2×1.25) =4/2.5-1.25×1.25/(5×0.5) =1.6-0.5×1.25 =1.6-0.625 =0.975 ≈0.98.