①535-384+279
②74+436-298
③422+233-195
④634-267-346
①72-45÷5
②68-19+27
③100-(55-17)
④57-7×4
⑤(89-57)÷8
⑥8+16÷4
①3.6﹣2.8+7.4﹣7.2
②1.25×1.6×25
③÷4
④÷[(﹣)×]