4. Range and precision

Range

Range is the difference between the maximum and minimum value re-presentable in a given format. Although it does not mean all values are re-presentable within that range.

The range of double precision numbers is:

• $-1\times 10^{308}\text{ to }-1\times 10^{-308}$ and $1\times 10^{308}\text{ to }1\times 10^{-308}$

Precision

Precision refers to how much information a representation gives us of a value.

• $3.14$ gives us $2$ digits of precision right of the decimal point.
• $3.142$ gives us $3$ digits of precision right of the decimal point.

More precision doesn’t mean more accuracy, $3.14$ is a more accurate representation of $\pi$ than $3.149$ even though it is less precise.