There are six numbers, the average number is 8, if one of the numbers is changed to 18, then the average number of these six numbers is 10, what should be the original number of this change.
有六个数，平均数是8，如果把其中的一个数改为18，那么这六个数的平均数为10，则这个改动的数原来应该是多少．
<gadget id="calculator">10 * 6</gadget>
<output>60</output>

<gadget id="calculator">8 * 6</gadget>
<output>48</output>

<gadget id="calculator">60 - 48</gadget>
<output>12</output>

<gadget id="calculator">18 - 12</gadget>
<output>6</output>

<result>6</result>