计算:
(3)(-3)×(-2)×(-4)×(-1);
(4).
(1)―(―0.2)+1;
(2);
(3);
计算
(1)(-1)+(-2)+(-4)+(-8)+8;
(2)3+(-1)+(-3)+1+(-4);
(3)(-23)-(-18)-1+(-15)+23;
(4)(-56)-48-(-48)-(-56).
化简:-(+5),+(-4),,―(―3.2),+(+7).