A book has 125 pages, how many numbers are needed to number the pages?
一本书有125页，一共需要多少个数字编页码．
<gadget id="calculator">2 * 90</gadget>
<output>180</output>

<gadget id="calculator">125 - 100</gadget>
<output>25</output>

<gadget id="calculator">25 + 1</gadget>
<output>26</output>

<gadget id="calculator">26 * 3</gadget>
<output>78</output>

<gadget id="calculator">9 + 180 + 78</gadget>
<output>267</output>

<result>267</result>