①15×[680÷(21+13)]
②2.5×(3.9+3.9+3.9+3.9)
③
④3×0.25+3×
75×22
①63.7﹣5.8﹣4.2
②×+÷11
③(++)×24
④5.96×[1÷(2.1﹣2.09)]
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﹣)+]
①6.4×2.5×1.25
②8.5×98%
③÷4+×
④×
①273﹣73﹣27
②1.25×9.78×80
③()×24
④[1﹣()]÷