Why do you have scientific notation?

Answer 1

Scientific notation makes it easier to express numbers of extremely small or large magnitude. For example, we could either say that something is .00000000068 meters long, or simply use scientific notation to write it as 6.8 x 10-10 meters.

There is also an "engineering" notation which is similar to scientific notation, but all exponents are multiples of 3. This is so we can introduce prefixes such as nano, micro, kilo, giga, etc. The number 573000 would be written as 5.73 x 105 in scientific notation, and 573 x 103 in engineering notation.