(2/5) of a number is exactly (2/3) of 50, what is this number?
一个数的(2/5)正好是50的(2/3)，这个数是多少．
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(2/3) / (2/5)</gadget>
<output>5/3 = around 1.666667</output>

<gadget id="calculator">50 * (5/3)</gadget>
<output>250/3 = around 83.333333</output>

<result>250/3 = around 83.333333</result>