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 fraction 6/1000000 written in scientific notation would be 6x10^-6 because the denominator was decreased by 6 decimal places.

The fraction 65/1000000 written in scientific notation would be 6.5x10^-5 because the denominator was decreased by 6 decimal places. One of the decimal places changed the numerator from 65 to 6.5.

A fraction smaller than 1 can be converted to scientific notation by decreasing the power of ten by one for each decimal place the denominator is decreased by.

Scientific notation numbers may be written in different forms. The number 6.5x10^-7 could also be written as 6.5e-7.