If the denominator of (3/8) is expanded by 3 times, then the amount to be added to the numerator is equal to the original number.
如果把(3/8)分母扩大3倍，那么分子要加上多少就与原数相等．
<gadget id="calculator">9 - 3</gadget>
<output>6</output>

<result>6</result>