-0.5=
15×=
4÷=
90×80%=
1-23%=
: 0.9: :0.75
①5++
②-(-)
③+++
④101×-
⑤-+0.875-0.4
⑥+-
+ = 50÷50%= = 3 -1.125=
1.9÷2.5÷0.4= ( )×18= = 1- =