Question

5.8乘5.8加0.58乘42 36.75乘99加36.75 17.9乘9.9加1.79 （简便运算）

Answer 1

5.8*5.8+0.58*42=.058*10*5.8+0.58*42=0.58*58+0.58*42=0.58*（58+42）=0.58*100=58

36.75*99+36.75=36.75*（99+1）=36.75*100=3675

17.9*9.9+1.79=17.9*9.9+17.9*0.1=17.9*（9.9+0.1）=17.9*10=179