Scientific notation is used to express very large or very small numbers. A number in scientific notation is written as the product of a number (integer or decimal) and a power of 10. The number has one digit to the left of the decimal point. The power of ten indicates how many places the decimal point was moved.

The number 6.5x10^-7 written in decimal format would be 0.00000065 because the decimal point was moved 7 places to the left to form the decimal 0.00000065.