Rouudoff error is the error caused by the finite word length employed in the
calculations. Roundoff error is more significant when small differences between large
numbers are calculated. Most computers have either 32 bit or 64 bit word length,
corresponding to approximately 7 or 13 significant decimal digits, respectively. Some
computers have extended precision capability, which increases the number of bits to 128.
Care must be exercised to ensure that enough significant digits are maintained in numerical
calculations so that roundoff is not significant.