计算下列各题,怎样简便怎样算. 105×13﹣1890÷18 [﹣(﹣)]÷ 25×+2.75÷ 27.4﹣52.8÷(1.9+2.1) (0.125×8﹣0.5)×4 9.25×9.9+0.925
9-3= 9-5= 18-2= 11-1= 9-6= 9-1=
19-4= 19-6= 16-5= 16-4= 16-0= 16-2=
7+2= 2+5= 12+5= 11+1= 7+3= 12+1=
5+2= 5+4= 15+1= 11+5= 5+5= 12+3=
12+4= 12+7= 11+4= 12+3= 16+2= 11+6=