642÷6= 0.9×99+0.9= 1.25×80= 2.5÷0.01=
÷ = 2﹣ ﹣ = 3﹣ ﹣ = ( ÷ )×30=
①25:x= :4
② x+37.5%x=
六(2)班捐款多少元?
②算术方法解: