7.28﹣(1.28+0.25) ÷[×(0.5+)]
23× 3.7×+1.3÷
① ②
③ ④
①36×()
②1.3×37.5%+2.7×
③ [()]
④13÷()×
①273﹣73﹣27
②1.25×9.78×80
③()×24
④[1﹣()]÷
①101×32
②2.74+8.67+7.26+11.33
③18.8﹣5.8﹣﹣4.2﹣
④×+÷
⑤0.888×125×73+999×3
⑥4﹣[3.75×(1.2﹣)+]
①1204+879+121
②74×60%+×25+0.6
③1.2÷×(0.6﹣)
④×[﹣(+)]