Write out all the one hundred natural numbers from 1 to 100, what is the sum of all the digits used.
把1到100的一百个自然数全部写出来，所用到的所有数码字的和是多少．
<gadget id="calculator">1 + 9</gadget>
<output>10</output>

<gadget id="calculator">10 / 2</gadget>
<output>5</output>

<gadget id="calculator">5 * 9 * 10 * 2</gadget>
<output>900</output>

<gadget id="calculator">900 + 1</gadget>
<output>901</output>

<result>901</result>