If rounding is
      necessary, the current
      <a href='#rounding-mode'><code>ROUNDING_MODE</code></a> setting is used.
    </p>
    <p>
      If the value of this BigNumber in normal notation has fewer fraction
      digits then is specified by <code>decimal_places</code>, the return value
      will be appended with zeros accordingly.
    </p>
    <p>
      Unlike <code>Number.prototype.toFixed</code>, which returns
      exponential notation if a number is greater or equal to 10<sup>21</sup>,
      th