① +( + )
② + + -
③ -( - )
④ - - -
+=
-=
3-=
0.8+=
×18=
×=
3.2×=
①和
②和
5÷0.02= 37.6-25.8= 234÷3= 45×7%=
2.4×2.5= ×5.6= ÷ = + =