数学医院.318﹣139﹣39=318﹣(139﹣39)=318﹣100=218 354﹣(154+72)=354﹣154+72=200+72=272
:4=0.75=9: =.
=3÷ =0.5= :10= %
=9÷ = :16= %= 填小数.
.
÷30=2÷5=18: = %