For example, the approximate number of stars in our Galaxy is 400 billion, or 400,000,000,000. Numbers of this size make the arithmetical operations of multiplication and division extremely cumbersome. Therefore, it is convenient to use what is known as scientific notation, which involves powers of ten. We begin by explaining exponents and their manipulations. By convention any number raised to the zeroth power is equal to 1.
Multiplication is accomplished by adding exponents.
Division is accomplished by subtracting exponents. Raising a number to a power is accomplished by multiplying exponents. Extracting a root is also accomplished by multiplying exponents. Scientific notation is the expression of any number as the product of a number between 1 and 10 times a power of 10. For the number 0.0005492 above the decimal is shifted four places to the right so that the power of 10 is also 4 but its algebraic sign is negative, or 5.492 x 10 -4 .