一个圆柱体积是210立方分米,与它等底等高的圆锥体的体积是 .
= : ==6÷ .
0.6==18÷ = :10= %
:8=0.8: =0.2= .
8: ===2.4÷ = (填小数)
%= ÷ =六成= +.