When a number is divided by 30, the quotient is 18 and the remainder is 12. What is the dividend?
一个数除以30，商是18，余数是12，被除数是多少．
<gadget id="calculator">30 * 18</gadget>
<output>540</output>

<gadget id="calculator">540 + 12</gadget>
<output>552</output>

<result>552</result>