The product of a number multiplied by (4/5) is (2/5). What is this number? What is the column
一个数乘(4/5)的积是(2/5)，这个数是多少？列式是多少
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(2/5) / (4/5)</gadget>
<output>1/2 = around 0.5</output>

<result>1/2 = around 0.5</result>