399.6*9-1998*0.8 巧算

399.6*9-1998*0.8 巧算
399.6*9-1998*0.8 巧算

399.6*9-1998*0.8 巧算
399.6*9-1998*0.8
=399.6*9-399.6*5*0.8
=399.6*(9-4)
=399.6*5
=(400-0.4)*5
=400*5-0.4*5
=2000-2
=1998

3996*10*9/10-1998*8/10=1998(2*9-8)/10=1998

=400*9-0.4*9-2000*0.8+2*0.8
=3600-1600-3.6+1.6
=2000-2
=1998

399.6*9-1998*0.8
=399.6*10-399.6-1998+1998*0.2
=3996-1998-399.6+399.6
1998

您好，很高兴为尊敬的您解答难题！
问：399.6*9-1998*0.8=？

399.6*9-1998*0.8
=400*9-0.4*9-2000*0.8+2*0.8
=3600-1600-3.6+1.6
=2000-2
=1998
谢谢！