用简便方法计算:
(1)×42;(2)(-0.25)12×413.
计算:
(1)-102n×100×(-10)2n-1;
(2)[(-a)·(-b)2·a2b3c]2;
(3)(x3)2÷x2÷x-x3÷(-x)4·(-x4);
(4)(-9)3××;
(5)xn+1·xn-1·x÷xm;
(6)a2·a3-(-a2)3-2a·(a2)3-2[(a3)3÷a3].
已知xm=3,xn=6,则x3m-2n的值是________.
计算:0.25×55=__________.
计算:(-m2)3÷(-m2)=________,(m4·m3)÷(m2·m4)=________.
计算(-10)2+(-10)0+10-2×(-102)的结果是__________.