①(254+236)÷7
②160×6÷8
③642÷6+208
④720÷2÷3
⑤36×4÷9
⑥693÷9+259
①1204+879+121
②74×60%+×25+0.6
③1.2÷×(0.6﹣)
④×[﹣(+)]