To make (7/25) 5 times larger, if you add 21 to the numerator, how much must the denominator be reduced
要使(7/25)扩大5倍，如果把分子加上21，那么分母就必须减少多少
<gadget id="calculator">25 / 5</gadget>
<output>5</output>

<result>5</result>