There are 36 chocolates in a box, my brother ate this box of chocolates (2/9). My younger brother ate this box of chocolates (1/6). The elder brother and the younger brother ate this box of chocolates together ((())/(())).
一盒巧克力36颗，哥哥吃了这盒巧克力的(2/9)．弟弟吃了这盒巧克力的(1/6)．哥哥和弟弟一共吃了这盒巧克力的((())/(()))．
<gadget id="calculator">2 / 9</gadget>
<output>2/9 = around 0.222222</output>

<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">(2/9) + (1/6)</gadget>
<output>7/18 = around 0.388889</output>

<result>7/18 = around 0.388889</result>