    underflow, division by zero, etc.  Instead, special IEEE numbers
    are returned as appropriate, such as <code class="code">infinity</code> for <code class="code">1.0&nbsp;/.&nbsp;0.0</code>,
    <code class="code">neg_infinity</code> for <code class="code">-1.0&nbsp;/.&nbsp;0.0</code>, and <code class="code">nan</code> ('not a number')
    for <code class="code">0.0&nbsp;/.&nbsp;0.0</code>.  These special numbers then propagate through
    floating-point computations as expected: for instance,
    <co