rec-pi1

pi

W3C sample WIRIS
[N/A] approx pi rational 22 7 
<math xmlns="http://www.w3.org/1998/Math/MathML">
  <apply>
    <csymbol cd="relation1">approx</csymbol>
    <csymbol cd="nums1">pi</csymbol>
    <apply>
      <csymbol cd="nums1">rational</csymbol>
      <cn>22</cn>
      <cn>7</cn>
    </apply>
  </apply>
</math>

Author: MathML 2 Recommendation