It is known that (1/4) of number A is equivalent to (1/5) of number B, then half of number A is equivalent to the number of B.
已知甲数的(1/4)相当于乙数的(1/5)，那么甲数的一半相当于乙数的多少．
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(1/4) / (1/5)</gadget>
<output>5/4 = around 1.25</output>

<gadget id="calculator">4 * (5/4)</gadget>
<output>5</output>

<gadget id="calculator">4 / 2 / 5</gadget>
<output>2/5 = around 0.4</output>

<result>2/5 = around 0.4</result>