mfracBhoriz11

W3C sample	WIRIS
	$\frac{1}{a}-\frac{1}{a+a+a+a}-\frac{1}{a+a+a+a+a+a+a+a+a+a}$

<math xmlns="http://www.w3.org/1998/Math/MathML">
  <mfrac>
    <mn>1</mn>
    <mi>a</mi>
  </mfrac>
  <mo>-</mo>
  <mfrac>
    <mn>1</mn>
    <mrow>
      <mi>a</mi>
      <mo>+</mo>
      <mi>a</mi>
      <mo>+</mo>
      <mi>a</mi>
      <mo>+</mo>
      <mi>a</mi>
    </mrow>
  </mfrac>
  <mo>-</mo>
  <mfrac>
    <mn>1</mn>
    <mrow>
      <mi>a</mi>
      <mo>+</mo>
      <mi>a</mi>
      <mo>+</mo>
      <mi>a</mi>
      <mo>+</mo>
      <mi>a</mi>
      <mo>+</mo>
      <mi>a</mi>
      <mo>+</mo>
      <mi>a</mi>
      <mo>+</mo>
      <mi>a</mi>
      <mo>+</mo>
      <mi>a</mi>
      <mo>+</mo>
      <mi>a</mi>
      <mo>+</mo>
      <mi>a</mi>
    </mrow>
  </mfrac>
</math>

Author: Robert Miner and Jeff Schaefer, Geometry Technologies