Number A is 30, Number B is (5/6) of Number A, number C is (2/5) of Number B, what is the number of C?
甲数是30，乙数是甲数的(5/6)，丙数是乙数的(2/5)，丙数是多少．
<gadget id="calculator">5 / 6</gadget>
<output>5/6 = around 0.833333</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">30 * (5/6) * (2/5)</gadget>
<output>10</output>

<result>10</result>