50-(3.88+0.57)
=50-(3.88+0.12-0.12+0.57)
=50-(4+0.45)
=50-4-0.45
=46-0.45
=45.55
=50-3.38-0.57
=50-4+0.62-1+0.43
=50-5+0.62+0.43
=45+1.05
=46.05
凑整之后可以简便运算
50-(3.88+0.57)
=50-(3.88+0.12-0.12+0.57)
=50-(4+0.45)
=50-4-0.45
=46-0.45
=45.55
50-(3.88+0.57)
=50-3.88-0.57
=50-4+0.12-0.57
=(50-4)+(0.12-0.57)
=46+(-0.45)
=45.55。
50-(3.88+0.57)
=50-3.88-0.57
=50-4+0.02-0.57
=46-0.55
=45.45