Chapter 3 - Scientific Measurement - 3.1 Using and Expressing Measurements - Sample Problem 3.4 - Page 69: 7

A) 9 x 10 meters B) 4 x 10^8 meters C) 2 x 10^-2 meters D) 9 x 10^3 meters E) 2 x 10^-3 meters F) 6 x 10^2 meters

The second significant digit is greater than 5, so you round up. The second significant digit is less than 5, so you don't round up. The second significant digit equals 5, so you round up. The second significant digit is less than 5, so you don't round up. The second significant digit is greater than 5, so you round up. The second significant digit is less than 5, so you don't round up.