**Negative scientific notation is expressing a number that is less than one, or is a decimal with the power of 10 and a negative exponent.** An example of a number that is less than one is the decimal 0.00064. To express this decimal in scientific notation, one has to use the power of 10 and a negative exponent.

To write this decimal in scientific notation, one moves the decimal point four places to the left and writes 6.4 multiplied by 10 raised to the negative four. To write any decimal number in negative scientific notation, one has to move the decimal point to the left to express negative exponents of 10.

For numbers that are greater than one, such as 2,100,000, one has to use a positive exponent, and one moves the decimal point to the right. In scientific notation, this number is 2.1 x 10^6.