甲数是乙数的40%,那么甲数和乙数的比是2:5. .(判断对错)
12: == :4=0.25= 折.
=2: =4÷ = %=0.2.
12÷ = :12=0.75= = %
0.75=6÷ = :12== %
1.75=7÷ ==28÷ =.