Be careful not to include the leading 0 in your count. We move the decimal point 13 places to the right, so the exponent of 10 is 13. The exponent is negative because we moved the decimal point to the right. This is what we should expect for a small number.
Scientific notation
A number is written in
scientific notation if it is written in the form
where
and
is an integer.
Converting standard notation to scientific notation
Write each number in scientific notation.
Distance to Andromeda Galaxy from Earth: 24,000,000,000,000,000,000,000 m
Diameter of Andromeda Galaxy: 1,300,000,000,000,000,000,000 m
Number of stars in Andromeda Galaxy: 1,000,000,000,000
Diameter of electron: 0.00000000000094 m
Probability of being struck by lightning in any single year: 0.00000143
To convert a number in
scientific notation to standard notation, simply reverse the process. Move the decimal
places to the right if
is positive or
places to the left if
is negative and add zeros as needed. Remember, if
is positive, the value of the number is greater than 1, and if
is negative, the value of the number is less than one.
Converting scientific notation to standard notation
Convert each number in scientific notation to standard notation.
Scientific notation, used with the rules of exponents, makes calculating with large or small numbers much easier than doing so using standard notation. For example, suppose we are asked to calculate the number of atoms in 1 L of water. Each water molecule contains 3 atoms (2 hydrogen and 1 oxygen). The average drop of water contains around
molecules of water and 1 L of water holds about
average drops. Therefore, there are approximately
atoms in 1 L of water. We simply multiply the decimal terms and add the exponents. Imagine having to perform the calculation without using scientific notation!