①2.65×1.7+7.35×1.7
②36×( + )
③54.2- +4.8-1
④0.7÷[( - )×24]
51×102 0.8××12.5 ×7÷×7
83.47﹣(23.47+11) 45×99+45 1÷2.5+2.5×0.8