Which of the following is closest to 10^180 – 10^20 ?	Answers.
A) 10^210
B) 10^180
C) 10^150
D) 10^90
E) 10^6
10^180 – 10^20   10^20 * (10^160 – 1)   as we know 10^2 - 1 means 100-1 and we get 99, which is approximately 100. hence (10^160 – 1) would remain as 10^160.   and 10^20 * 10^160 = 10^180. Answer is 10^180.
<result>B</result>
Which of the following is closest to 10^180 – 10^20 ?