Which of the following is closest to 10^150 – 10^30 ?	Choices:	A) 10^210	B) 10^180	C) 10^150	D) 10^90	E) 10^6
10^150 – 10^30   10^30 * (10^120 – 1)   as we know 10^2 - 1 means 100-1 and we get 99, which is approximately 100. hence (10^120 – 1) would remain as 10^120.   and 10^30 * 10^120 = 10^150. Answer is 10^150.
<result>C</result>
Which of the following is closest to 10^150 – 10^30 ?