13-7/11-(1/11)*15.
13-7/11-(1/11)*15．
<gadget id="calculator">7 / 11</gadget>
<output>7/11 = around 0.636364</output>

<gadget id="calculator">1 / 11</gadget>
<output>1/11 = around 0.090909</output>

<gadget id="calculator">(1/11) * 15</gadget>
<output>15/11 = around 1.363636</output>

<gadget id="calculator">13 - (7/11) - (15/11)</gadget>
<output>11</output>

<result>11</result>