(1/7) plus 2 (1/7) is 5 (1/7), that is how much.
3个(1/7)加上2个(1/7)是5个(1/7)，就是多少．
<gadget id="calculator">7 / 1</gadget>
<output>7</output>

<gadget id="calculator">3 / 7</gadget>
<output>3/7 = around 0.428571</output>

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

<gadget id="calculator">(3/7) + (2/7)</gadget>
<output>5/7 = around 0.714286</output>

<result>5/7 = around 0.714286</result>