⑴5795.5795/5.795*579.5 ⑵45.3*3.2+578*0.68+12*9.5 ⑶88.8/3.14*62.8*24.3/8/8.1

问题描述:

⑴5795.5795/5.795*579.5 ⑵45.3*3.2+578*0.68+12*9.5 ⑶88.8/3.14*62.8*24.3/8/8.1
⑷0.1949*0.19951995-0.1995*0.19491949 ⑸18.9*178.178+0.49-17.8*189.189
⑹3.42*76.3+76.3*5.76+9.18*23.7
要简便算法!

(4)0.1949*0.19951995-0.1995*19491949=0.1949*(0.1995+0.00001995)-0.1995*(0.1949+0.00001949)
用乘法分配律:0.1949*(0.1995+0.00001995)-0.1995*(0.1949+0.00001949)=0.1995*(0.1949+0.00001949)-0.1995*(0.1949+0.00001949)=0.1995*(0.1949+0.00001949-0.1949-0.00001949)=0.1995*0=0