When a number is divided by 4, the quotient is 5. When the remainder is the largest, what is the dividend?
一个数除以4，商是5，当余数最大时，被除数是多少
<gadget id="calculator">4 * 5</gadget>
<output>20</output>

<gadget id="calculator">4 - 1</gadget>
<output>3</output>

<gadget id="calculator">20 + 3</gadget>
<output>23</output>

<result>23</result>