Estimate the total number of hours Americans spend stuck in traffic each year. If you are unfamiliar with estimation techniques, you may find it difficult to know how to begin solving this problem. This tutorial is designed to introduce you to the art of estimation. Learning to calculate rough estimates has many applications both in the sciences and in other fields. The ability to estimate the order of magnitude of unknown quantities can produce invaluable guides for measurements and planning. When estimating, you are looking for a number that is within an order of magnitude (i. e., a power of ten) of the actual value. This is a broad range, so it is neither necessary nor desirable to work with precise numbers. You want numbers that are both reasonable and easy to use incalculations. For example, there are 365 days in a year. For the purposes of estimation, 365 is unnecessarily precise; 3 x 102 or 4 x 102 are both reasonable approximations and are more convenient for calculation. There is no definite rule concerning the precision of approximations. How coarse you make your approximations depends on how you plan to use the numbers and how precise you want your estimate to be. When beginning any approximation problem, ask yourself, "What do I need to know in order to solve this?" This particular problem asks about Americans, so the total number of Americans is a good place to start. In actuality, there are a little over 325 million. Choose a convenient approximation for this value. A.