The sum of the numbers is 9, how many four-digit numbers including the number 0 are there.
数字和为9，含数字0的四位数共有多少个．
<gadget id="calculator">11 * 10 * 9</gadget>
<output>990</output>

<gadget id="calculator">3 * 2 * 1</gadget>
<output>6</output>

<gadget id="calculator">990 / 6</gadget>
<output>165</output>

<gadget id="calculator">4 * 2</gadget>
<output>8</output>

<gadget id="calculator">9 + 3</gadget>
<output>12</output>

<gadget id="calculator">12 * 4</gadget>
<output>48</output>

<gadget id="calculator">8 + 48</gadget>
<output>56</output>

<gadget id="calculator">165 - 56</gadget>
<output>109</output>

<result>109</result>