How much more is the sum of 2 (2/3) than the product of 2 (2/3).
2个(2/3)的和比2个(2/3)的积多多少．
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">(2/3) * (2/3)</gadget>
<output>4/9 = around 0.444444</output>

<gadget id="calculator">(2/3) - (4/9)</gadget>
<output>2/9 = around 0.222222</output>

<gadget id="calculator">(2/3) + (2/9)</gadget>
<output>8/9 = around 0.888889</output>

<result>8/9 = around 0.888889</result>