10% of number A is equal to (2/5) of number B, and number A is equal to number B.
甲数的10%与乙数的(2/5)相等，甲数是乙数的多少．
<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

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

<gadget id="calculator">(1/10) / (2/5)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 * (1/4)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 / (1/4)</gadget>
<output>4</output>

<result>4</result>