A book has 623 pages, how many times does the number 3 appear in the page number?
一本书有623页，数字3在页码中共出现多少次．
<gadget id="calculator">10 + 10</gadget>
<output>20</output>

<gadget id="calculator">100 + 20</gadget>
<output>120</output>

<gadget id="calculator">4 * 20</gadget>
<output>80</output>

<gadget id="calculator">20 + 120 + 80 + 3</gadget>
<output>223</output>

<result>223</result>