①0.53×2.5+
②25×0.032×12.5
③ [()×]
④6.83+17.9﹣0.83+32.1
①7.4﹣6.62+20.6﹣13.38
②×+×
③(-+)÷
④2×0.8×12.5×50%
⑤÷(÷+)
⑥×[1÷(+)]