MathML Fundamentals - Style Change mstyle

The mstyle element is used to make style changes that affect the rendering of its contents. MathML Fundamentals

( a b ) + ( a b )

MathML

<math mathsize="45">
    <mrow>
        <mo>(</mo>
        <mfrac>
            <mi>a</mi>
            <mi>b</mi>
        </mfrac>
        <mo>)</mo>
    </mrow>
    <mo>+</mo>
    <mstyle maxsize="1">
        <mrow>
            <mo>(</mo>
            <mfrac>
                <mi>a</mi>
                <mi>b</mi>
            </mfrac>
            <mo>)</mo>
        </mrow>
    </mstyle>
</math>