把2米长的圆木锯成每段长0.5米,要15分钟;如果锯成每段0.4米,要 分钟.
0.25= ÷8== : .
40: =8:10= /5= (填小数)
=18: = ÷40= [填小数].
==10÷ = ÷36.
:16= ÷ ==0.125.