5000/2500=2, if the divisor is reduced by 500, what should be the divisor to keep the quotient unchanged.
5000/2500=2，如果除数减少500，要使商不变，被除数应该多少．
<gadget id="calculator">5_000 / 2_500</gadget>
<output>2</output>

<gadget id="calculator">2_500 - 500</gadget>
<output>2_000</output>

<gadget id="calculator">2 * 2_000</gadget>
<output>4_000</output>

<gadget id="calculator">5_000 - 4_000</gadget>
<output>1_000</output>

<result>1_000</result>