内容介绍：77-19-16= 88-34-18= 85-36+27= 12+79-62= 51-27+28= 51-42+53= 77-65-6= 71-52+36= 75-24-26= 75+24-23= 32+45-38= 81-45+36= 24-16+40=63-12-42= 53-37+15= 63-23-28= 48-26+18= 83-27+10= 54-21-18= 65-33-18= 68