3.14×7=
25.12÷3.14 =
25×50%=
5.5÷50%=
3.14×9= 7.2×= 1.25××0.8=
3.14×2.25= 12×()=
1×= ×10= += ×9×=
-= 6×= ×= 5-7×=
= = =
= =