There is a batch of working parts, sold in January (2/5), and sold 10% in February. How many of these parts have been sold in total in the past two months?
有一批工作零件，1月份卖出(2/5)，2月份卖出10%．这两个月一共卖出这批零件的多少．
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(2/5) + (1/10)</gadget>
<output>1/2 = around 0.5</output>

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