It is known that a and b are natural numbers, (4/15)=(1/(a))+(1/(b)), then what is the minimum value of a+b.
已知a，b为自然数，(4/15)=(1/(a))+(1/(b))，那么a+b的最小值是多少．
<gadget id="calculator">10 + 6</gadget>
<output>16</output>

<result>16</result>