Originally, 189 numbers were used to compile a storybook, and 10 pages were added later, so how many more numbers should be added to number the pages?
编一本故事书原先正好用了189个数字，后来又增加了10页，那么还要增加多少个数字编页码．
<gadget id="calculator">3 * 10</gadget>
<output>30</output>

<result>30</result>