What is 8.953 rounded to the nearest hundred

Can someone explain the elimination method to me for this problem?

Asequence {an} is defined recursively, with a1 = 1, a2 = 2 and, for n > 2, an = an-1 an-2 . find the term a241. a) 0 b) 1 c) 2 d) 1 2

2.5 milligrams is equivalent to how many grams