If a is subtracted from the numerator of the fraction (29/43) and a is added to the denominator, the resulting new fraction becomes (3/5) after being reduced, what is the natural number a=?
如果将分数(29/43)的分子减去a，分母加上a，所得的新分数约分后变为(3/5)，自然数a=多少．
<gadget id="calculator">3 + 5</gadget>
<output>8</output>

<gadget id="calculator">72 / 8</gadget>
<output>9</output>

<gadget id="calculator">9 * 3</gadget>
<output>27</output>

<gadget id="calculator">29 - 27</gadget>
<output>2</output>

<result>2</result>