Question

2.25*3.14*4+3.14= (1/15-1/51)*17*5= 怎样简算，要过程啊

Answer 1

2.25*3.14*4+3.14 =（2.25*4+1）*3.14 =[(2+0.25)*4+1]*3.14 =(2*4+0.25*4+1)*3.14 =(8+1+1)*3.14 =10*3.14 =31.4 (1/15-1/51)*17*5 =1/15*5*7-1/51*17*5 =1/3*17-1/3*5 =1/3*(17-5) =1/3*12 =4 补充： 第二道的第二行的7应该是17，打错了~~