When a number is divided by 7, the quotient is 79 and the remainder is 4. What is this number?
一个数除以7，商79余4，这个数是多少
<gadget id="calculator">79 * 7</gadget>
<output>553</output>

<gadget id="calculator">553 + 4</gadget>
<output>557</output>

<result>557</result>