The <mfrac> MathML element is used to display fractions. It can also be used to mark up fraction-like objects such as binomial coefficients and Legendre symbols.
<mfrac>numerator denominator</mfrac>This element's attributes include the global MathML attributes as well as the following attributes:
denomalign The alignment of the denominator under the fraction. Possible values are: left, center (default), and right.
linethicknessA <length-percentage> indicating the thickness of the horizontal fraction line.
numalign The alignment of the numerator over the fraction. Possible values are: left, center (default), and right.
Note: For the linethickness attribute, some browsers may also accept the deprecated values medium, thin and thick (whose exact interpretation is left to implementers) or legacy MathML lengths.
The following MathML code should render as a fraction with numerator "a + 2" and denominator "3 − b":
<math display="block">
<mfrac>
<mrow>
<mi>a</mi>
<mo>+</mo>
<mn>2</mn>
</mrow>
<mrow>
<mn>3</mn>
<mo>−</mo>
<mi>b</mi>
</mrow>
</mfrac>
</math>The following MathML code should render as a binomial coefficient:
<math display="block">
<mrow>
<mo>(</mo>
<mfrac linethickness="0">
<mi>n</mi>
<mi>k</mi>
</mfrac>
<mo>)</mo>
</mrow>
</math>