The number of A is (2/5), and the number of B is (1/2) of the number of A. What is the sum of the two numbers of A and B?
甲数是(2/5)，乙数是甲数的(1/2)，甲、乙两数的和是多少？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(2/5) * (1/2)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(1/5) + (2/5)</gadget>
<output>3/5 = around 0.6</output>

<result>3/5 = around 0.6</result>