In Science one often needs to work with very large or very small numbers. These can be written more easily in scientific notation, in the general form

where dd is a decimal number between 0 and 10 that is rounded off to a few decimal places. ee is known as the *exponent* and is an integer.
If e>0e>0 it represents how many times the decimal place in dd should be moved to the right. If e<0e<0, then it represents how many times the decimal place in dd should be moved to the left. For example 3,24×1033,24×103 represents 3240 (the decimal moved three places to the right) and 3,24×10-33,24×10-3 represents 0,003240,00324 (the decimal moved three places to the left).

If a number must be converted into scientific notation, we need to work out how many times the number must be multiplied or divided by 10 to make it into a number between 1 and 10 (i.e. the value of ee) and what this number between 1 and 10 is (the value of dd). We do this by counting the number of decimal places the decimal comma must move.

For example, write the speed of light in scientific notation, to two decimal places. The speed of light is 299 792 458 m··s-1-1. First, find where the decimal comma must go for two decimal places (to find dd) and then count how many places there are after the decimal comma to determine ee.

In this example, the decimal comma must go after the first 2, but since the number after the 9 is 7, d=3,00d=3,00. e=8e=8 because there are 8 digits left after the decimal comma. So the speed of light in scientific notation, to two decimal places is 3,00 ×× 1088 m··s-1-1.

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