计算.(1) (2)(3) (4)3x-( 2x-4) +(2x-1)
计算:
计算:(1)3.2+﹣7.2+|﹣|. (2)(1﹣)÷3×(﹣12)﹣42.
|-3|-(-1)0+()-1-(-1)4.
(.