①
②
③13×-11×
④(×25%)×(1.3×40)
275+399=
20×35=
13.7-7=
0.4×3.7×250
36×()
7.38-1.45+2.62
2.07×50×0.2
25×125%×32 3.5×+5.5×80%+0.8 ×[60%-(-40%)]