(3/5) of a number is 4 less than (4/7) of 49, what is this number?
一个数的(3/5)比49的(4/7)少4，这个数是多少？
<gadget id="calculator">4 / 7</gadget>
<output>4/7 = around 0.571429</output>

<gadget id="calculator">49 * (4/7)</gadget>
<output>28</output>

<gadget id="calculator">28 - 4</gadget>
<output>24</output>

<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">24 / (3/5)</gadget>
<output>40</output>

<result>40</result>