I'm not sure of my answers I think #18 should be D)4

17. When multiplying 1.04 x 0.31 the number of significant figures in the answer should be A) 2 B) 3 C) 4 D) 5 18. How many significant figures should be in the answer obtained by adding 0.04, 31.2, and 100.0? A) 3 B) 2 C) 5 D) 4 19. 10' equals 103 A) 104 B) 102 C) 10-2 D) 104