Help Scientific Notation Problem?

First deal with the exponents. Exponents are the number of times you multiply by 10. So it's like you take 4.5/8.1, and then multiply it by 10 9 times, and then divide it by 10 -11 times. Dividing negative times means multiplying, so divide 4.5 by 8.1 and then multiply by 10 20 times. The answer is 0.56 multiplied by 10 20 times, or 5.6x10^19 (you use up one multiplication by 10 to get from 0.56 to 5.6).