Starting from 9, write down the multiples of 9 one by one until 999, which becomes a very large number: 918273645546372819099...990999. How many digits does this number have?
从9开始，把9的倍数依次写下去，一直写到999，成了一个很大的数：918273645546372819099…990999．这数共有多少位．
<gadget id="calculator">2 * 10</gadget>
<output>20</output>

<gadget id="calculator">100 * 3</gadget>
<output>300</output>

<gadget id="calculator">1 + 20 + 300</gadget>
<output>321</output>

<result>321</result>