What is the number when a number is divided by 23 and the quotient of 15 is 21?
一个数除以23商15余21，这个数是多少．
<gadget id="calculator">23 * 15</gadget>
<output>345</output>

<gadget id="calculator">345 + 21</gadget>
<output>366</output>

<result>366</result>