The mfrac element is used to display a fraction.
<math> <mfrac> <mi>y</mi> <mn>3</mn> </mfrac> </math>
If the fraction contains a single element in the numerator and a single element in the denominator, then the simple coding show above will work.
<math>
<mfrac>
<mrow>
<mn>3</mn>
<mi>y</mi>
</mrow>
<mrow>
<mn>12</mn>
</mrow>
</mfrac>
</math>
If either the numerator or the denominator, or both, contain multiple elements, then use the mrow element to specify which elements go in the numerator and which go in the denominator.
<math>
<mfrac>
<mrow>
<mn>2</mn>
<mi>x</mi>
<mo>-</mo>
<mn>14</mn>
<mo>+</mo>
<mn>3</mn>
<mo>(</mo>
<mi>x</mi>
<mo>+</mo>
<mn>2</mn>
<mo>)</mo>
</mrow>
<mrow>
<mn>6</mn>
<mo>(</mo>
<mn>2</mn>
<mi>x</mi>
<mo>+</mo>
<mn>2</mn>
<mo>-</mo>
<mn>4</mn>
<mo>(</mo>
<mn>4</mn>
<mi>x</mi>
<mo>-</mo>
<mn>2</mn>
<mo>)</mo>
<mo>)</mo>
</mrow>
</mfrac>
</math>
Using the row element and the mo element to define parentheses, you can define some pretty complex fractional expressions, as shown above.
<math>
<mfrac>
<mfrac bevelled="true">
<mi>y</mi>
<mn>3</mn>
</mfrac>
<mn>12</mn>
</mfrac>
</math>
By nesting mfrac elements you can create multi-level fractions. A multi-level fraction can sometimes be made more understandable by using a diagonal fraction bar. To create a diagonal fraction bar, add the bevelled attribute, set to "true", to the mfrac opening tag.
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