Sometimes the numbers that we work with are very large or very small, and several zeros are used to hold the decimal place. With such numbers, we may use a different way of writing them. It is called scientific notation. If you already know how to write and interpret numbers in scientific notation, feel free to move on to the next topic. Or, test your knowledge with the quick quiz at the end of this section, then decide how to continue. Before I discuss scientific notation, I want to be sure you are familiar with exponents and powers of 10.