每条船最多能乘6人,27人要过河,要 条船.
3:8=18÷ ═ %= .小数.
÷8===15÷ = ÷32= (填小数)
0.3==12÷ = :30= %
÷40=20: =0.8= : .
3÷ == :12=六成= %