The number A is 400, the number B is twice the number A, what is the sum of the two numbers A and B?
甲数是400，乙数是甲数的2倍，甲乙两数的和是多少．
<gadget id="calculator">400 * 2</gadget>
<output>800</output>

<gadget id="calculator">800 + 400</gadget>
<output>1_200</output>

<result>1_200</result>