The remainder returned by mod is non-negative. Furthermore, <code>div$(!a.!d)*!d+mod$(!a.!d):!a</code> for all integer <code>!a</code> and <code>!d</code>, <code>!d:~0</code>.
  ( enter
  =     put$"Enter two integer numbers, separated by space:"
      &amp; get':(~/#?k_~/#?m|quit:?k)
    |     out
        $ "You must enter two integer numbers! Enter \"quit\" if you don't know how to do that."
      &amp; !enter
  )
&amp; !enter
&amp; !k:~quit
&amp; out$("You entered" !k and !m ". Now look:")
&amp; out$("Sum:" !k+!m)
&amp; out$("Difference:" !k+-1*!m)
&amp; out$("Product:" !k*!m)
&amp; out$("Integer division:" div$(!k.!m))
&amp; out$("Remainder:" mod$(!k.!m))
&amp; out$("Exponentiation:" !k^!m)
&amp; done;