How much is the total of two 10-yuan coins and one 50-cent coin?
2张10元、1枚5角硬币一共是多少元．
<gadget id="calculator">10 * 2</gadget>
<output>20</output>

<gadget id="calculator">20 + 0.5</gadget>
<output>20.5</output>

<result>20.5</result>