ElementaryMathExamples-mscarry02

test for : mscarry crossout="horizontalstrike"

W3C sample	WIRIS
	$21\mathrm{2,327}-\mathrm{1,156}\mathrm{1,171}$

<math xmlns="http://www.w3.org/1998/Math/MathML">
  <mstack>
    <mscarries location="nw">
      <none/>
      <mscarry crossout="horizontalstrike" location="n">
        <mn>2</mn>
      </mscarry>
      <mn>1</mn>
      <none/>
    </mscarries>
    <mn>2,327</mn>
    <msrow>
      <mo>-</mo>
      <mn>1,156</mn>
    </msrow>
    <msline/>
    <mn>1,171</mn>
  </mstack>
</math>

Author: Yecheng Gu