计算:(1); (2)(-6)×5×;(3)(-4)×7×(-1)×(-0.25);(4)
×[-(-)]
1.8×8.6+1.8×1.3+18%
100﹣98+96﹣94+92﹣90+…+76﹣74+72=
11+192+193+19994+199995=
=