The mfenced element provides a convenient form in which to express common constructs involving fences (i.e. braces, brackets, and parentheses), possibly including separators (such as comma) between the arguments. MathML Fundamentals
<math mathsize="100"> <mspace linebreak="newline" indentalign="center"></mspace> <mtext style="border:1px;">MFenced Test</mtext> <mspace linebreak="newline" indentalign="center"></mspace> <mfenced style="border:1px"> <mrow> <mi>a</mi> <mo>+</mo> <mi>b</mi> </mrow> </mfenced> <mspace linebreak="newline" indentalign="center"></mspace> <mfenced style="border:1px"> <mfrac style="border:1px"> <mi>a</mi> <mi>b</mi> </mfrac> <mo>+</mo> <mi>c</mi> </mfenced> <mfenced style="border:1px" open="{" close="}"> <mfrac style="border:1px"> <mi>a</mi> <mi>b</mi> </mfrac> <mi>b</mi> <mi>c</mi> </mfenced> <mfenced style="border:1px" open="⌈" close="⌉" separators="|"> <mfrac style="border:1px"> <mi>a</mi> <mi>b</mi> </mfrac> <mi>b</mi> <mi>c</mi> </mfenced> <mspace linebreak="newline" indentalign="center"></mspace> <mfenced style="border:1px" separators="|"> <mi>a</mi> <mi>b</mi> <mi>c</mi> </mfenced> <mspace linebreak="newline" indentalign="center"></mspace> <mfenced style="border:1px" separators=",|"> <mi>a</mi> <mi>b</mi> <mi>c</mi> <mi>d</mi> <mi>e</mi> </mfenced> </math>