Use nine digits from 1 to 9 to form several numbers (use each number once) to obtain a sum of 99. How many different ways of group numbers are there?
用1～9九个数码组成若干个(每个数码用一次)求得和为99，共有多少种不同的组数方法？
<gadget id="calculator">99 - 45</gadget>
<output>54</output>

<gadget id="calculator">10 - 1</gadget>
<output>9</output>

<gadget id="calculator">54 / 9</gadget>
<output>6</output>

<gadget id="calculator">6 * 5 * 4</gadget>
<output>120</output>

<gadget id="calculator">7 * 2 * 2</gadget>
<output>28</output>

<gadget id="calculator">120 + 28 + 8</gadget>
<output>156</output>

<result>156</result>