251*4+(753-251)*2=how much.
251*4+(753-251)*2=多少．
<gadget id="calculator">251 * 4</gadget>
<output>1_004</output>

<gadget id="calculator">753 - 251</gadget>
<output>502</output>

<gadget id="calculator">502 * 2</gadget>
<output>1_004</output>

<gadget id="calculator">1_004 + 1_004</gadget>
<output>2_008</output>

<result>2_008</result>