两道数学计算题(用简便算法)(1)19.8*37-199.8*1.9+1998*0.82(2)13分之8*[4分之3-(16分之3-4分之1)]希望列出简便过程(列出加分)
问题描述:
两道数学计算题(用简便算法)
(1)19.8*37-199.8*1.9+1998*0.82
(2)13分之8*[4分之3-(16分之3-4分之1)]
希望列出简便过程(列出加分)
答
(1)19.98*37-199.8*1.9+1998*0.82
=19.98*37-19.98*10*1.9+19.98*100*0.82
=19.98*37-19.98*19+19.98*82
=19.98*(37-19+82)
=19.98*100
=1998
(2)8/13*[3/3-(3/16-1/4)]
=8/13*[3/4-3/16+1/4]
=8/13*(1-3/16)
=8/13*13/16
=1/2
答
(1)19.8*37-199.8*1.9+1998*0.82=198*0.1*37-199.8*1.9+199.8*10*0.82=198*3.7-199.8*1.9+1998*8.2 =198*(3.7-1.9+8.2)=198*10=1980(2)13分之8*[4分之3-(16分之3-4分之1)]=8/13*[3/4-(3/16-1/4)]=8/13*(3/4-3/...