13/19+18*(13/19).
13/19+18*(13/19)．
<gadget id="calculator">13 / 19</gadget>
<output>13/19 = around 0.684211</output>

<gadget id="calculator">18 * (13/19)</gadget>
<output>234/19 = around 12.315789</output>

<gadget id="calculator">(13/19) + (234/19)</gadget>
<output>13</output>

<result>13</result>