(1)2abc^2*(-1\3a^2b^3cx)=-2/3a^3b^4c^3 x(2)(-2ab)^3*(-a^2c)*3ab^2==-8a^3b^3*(-a^2c)*3ab^2=24a^6b^5c（3）0.04^997*（（-5）^997）^2==0.04^997 ×25^997=(0.04×25)^997=1