When a number is expressed in scientific notation, it is written as a product of a factor and a power of 10. The factor must be greater than or equal to 1 and less than 10. Multiplying by a positive power of 10 moves the decimal point to the right the same number of places as the exponent.
Scientific notation is also used to express very small numbers. Multiplying by a negative power of 10 moves the decimal point to the left the same number of places as the absolute value of the exponent.