What is the sum of 400 plus 25 minus 21? what is the correct formula
400加上25减去21的差，和是多少？正确的算式是多少
<gadget id="calculator">25 - 21</gadget>
<output>4</output>

<gadget id="calculator">400 + 4</gadget>
<output>404</output>

<result>404</result>