a/12=c, the dividend is enlarged by 5 times, how much should the divisor increase to keep the quotient unchanged.
a/12=c，被除数扩大5倍，要想使商不变，除数应该增加多少．
<gadget id="calculator">12 * 5</gadget>
<output>60</output>

<gadget id="calculator">60 - 12</gadget>
<output>48</output>

<result>48</result>