①5×5+8 =25+8 =33(元) 答:买5本笔记本和一个文具盒,应付33元. ②×4+14 =12+14 =26(元) 答:买1支钢笔和4支铅笔,应付26元. (3)100-14×2 =100-28 =72(元) 答:应找回72元.