One piece is 5 yuan, one piece is 2 yuan, one piece is 1 yuan, and one piece is 50 cents.
一张5元，一张2元，一张1元，一张5角合起来是多少元．
<gadget id="calculator">5 + 2 + 1 + 0.5</gadget>
<output>8.5</output>

<result>8.5</result>