Calculate with a simple method: (15/13)*(1/7)+(6/7)*(15/13).
用简便方法计算：(15/13)*(1/7)+(6/7)*(15/13)．
<gadget id="calculator">15 / 13</gadget>
<output>15/13 = around 1.153846</output>

<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">(15/13) * (1/7)</gadget>
<output>15/91 = around 0.164835</output>

<gadget id="calculator">6 / 7</gadget>
<output>6/7 = around 0.857143</output>

<gadget id="calculator">(6/7) * (15/13)</gadget>
<output>90/91 = around 0.989011</output>

<gadget id="calculator">(15/91) + (90/91)</gadget>
<output>15/13 = around 1.153846</output>

<result>15/13 = around 1.153846</result>