Simple calculation: (8/17)*(4/13)+(4/17)*(9/13).
简便运算：(8/17)*(4/13)+(4/17)*(9/13)．
<gadget id="calculator">8 / 17</gadget>
<output>8/17 = around 0.470588</output>

<gadget id="calculator">4 / 13</gadget>
<output>4/13 = around 0.307692</output>

<gadget id="calculator">(8/17) * (4/13)</gadget>
<output>32/221 = around 0.144796</output>

<gadget id="calculator">4 / 17</gadget>
<output>4/17 = around 0.235294</output>

<gadget id="calculator">9 / 13</gadget>
<output>9/13 = around 0.692308</output>

<gadget id="calculator">(4/17) * (9/13)</gadget>
<output>36/221 = around 0.162896</output>

<gadget id="calculator">(32/221) + (36/221)</gadget>
<output>4/13 = around 0.307692</output>

<result>4/13 = around 0.307692</result>