It is known that ab=12, bc=10, ad=18, cd=how many (a, b, c, d are all natural numbers)
已知ab=12，bc=10，ad=18，cd=多少(a、b、c、d均为自然数)
<gadget id="calculator">18 / 12</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">10 * (3/2)</gadget>
<output>15</output>

<result>15</result>