x+60%x=28
0.3:90%=12:x
3.2﹣2.5x=0.7
500-213= 10÷10%= 0.25+2.83= 1.25×0.8= 3.7-3.7÷3.7=
92-33= + = × = 9÷ = ( - )×20=
642÷6= 0.9×99+0.9= 1.25×80= 2.5÷0.01=
÷ = 2﹣ ﹣ = 3﹣ ﹣ = ( ÷ )×30=
①
②∶=x∶
③=8∶3
④
我写的算式是:□×□和□×□。