①7.2÷2.5 ÷2
②(2.4÷6.8)÷4
③1.2÷0.6-0.4×0.5
④27×1.5÷0.9
①57.6﹣18.15+32.4﹣11.85
②78×25+1764÷49
③2.5×32×12.5
④3.6×[(37.5+18.5)÷2.8]
⑤÷[(﹣)×]
⑥199×99+178+21
①612÷18+780÷30
②2.5×32×12.5
③5÷(0.5+)×
④
⑤()
⑥16×+8×+12÷25