It's answer will be 36x10^5 As we have (4x10^10)(9x10^-5) All terms of this expression are being multiplied So we will solve it in two parts, simple terms and terms having powers (4x9)(10^10x10^-5) As we know when same terms having some powers are multiplied, their powers are added (36)(10^(10-5)) (36)(10^5) So it will become 36x10^5