There are three numbers a, b, and c, a*b=24, a*c=36, b*c=54, then a+b+c=how much.
有a，b，c三个数，a*b=24，a*c=36，b*c=54，则a+b+c=多少．
<gadget id="calculator">4 + 6 + 9</gadget>
<output>19</output>

<result>19</result>