x -40%x = x:=÷20%
⑴12×=
×7.2=
12÷=
×=
⑵0÷=
0.42÷=
÷=
+=
⑶÷2=
1.8×=
÷0.5=
-=
⑷÷+=
1--=
×9 ÷=
×÷×=
1﹣35%= 6.5×20%= 1.5÷= =