hexcolors2

W3C sample	WIRIS
	$\begin{matrix} A + A \\ 1 + 1 \\ 1 + 1 \end{matrix}$

<math xmlns="http://www.w3.org/1998/Math/MathML">
  <mtable>
    <mtr>
      <mtd>
        <mrow>
          <mi color="#f00">A</mi>
          <mo>+</mo>
          <mi color="#0000ff">A</mi>
        </mrow>
      </mtd>
    </mtr>
    <mtr>
      <mtd>
        <mrow>
          <mn mathcolor="#f00">1</mn>
          <mo>+</mo>
          <mn mathcolor="#0000ff">1</mn>
        </mrow>
      </mtd>
    </mtr>
    <mtr>
      <mtd>
        <mrow>
          <mn mathbackground="#f00">1</mn>
          <mo>+</mo>
          <mn mathbackground="#0000ff">1</mn>
        </mrow>
      </mtd>
    </mtr>
  </mtable>
</math>

Author: Robert Miner and Jeff Schaefer, Geometry Technologies; Neil Soiffer, Wolfram Research