How much is 4 (1/7) plus 2 (1/7).
4个(1/7)加2个(1/7)是多少．
<gadget id="calculator">7 / 1</gadget>
<output>7</output>

<gadget id="calculator">4 / 7</gadget>
<output>4/7 = around 0.571429</output>

<gadget id="calculator">2 / 7</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">(4/7) + (2/7)</gadget>
<output>6/7 = around 0.857143</output>

<result>6/7 = around 0.857143</result>