Bài 8. Luyện tập


1. Tính nhẩm\(\eqalign{ & a)\,\,80\,\, - \,\,20\,\, - \,\,10\,\, = \,...\, \cr & \,\,\,\,\,80\,\, - \,\,30\,\,\, = \,...\, \cr & b)\,70\,\,\, - \,\,\,30\,\, - \,\,20\,\, = \,...\, \cr & \,\,\,\,\,70\,\, - \,\,50\,\,\, = \,...\, \cr & c)\,\,90\,\, - \,\,20\,\, -...