因为=20%,所以吨=20%吨. ;如果a×=b,那么a<b. .
=2.5:( )=125%=20÷( )=.
5: ==0.25= %
2.5÷ ==15: = %= (小数)
÷8==0.375=9÷ =; 填质数:21= + ; = × .
= %=2÷ =四成.