In a division formula with a remainder, the quotient is 30 and the remainder is 20. What is the smallest dividend?
在一个有余数的除法算式里，商是30，余数是20，被除数最小是多少．
<gadget id="calculator">21 * 30</gadget>
<output>630</output>

<gadget id="calculator">630 + 20</gadget>
<output>650</output>

<result>650</result>