(1.36+2.87)+0.64=how much.
(1.36+2.87)+0.64=多少．
<gadget id="calculator">1.36 + 2.87</gadget>
<output>4.23</output>

<gadget id="calculator">4.23 + 0.64</gadget>
<output>4.87</output>

<result>4.87</result>