The average of the four numbers a, b, c, and d is 16. If the average of these four numbers is to be increased to 18, how much should one of the numbers be increased?
a，b，c，d四个数的平均数是16，如果要让这四个数的平均数提高到18，其中一个数要增加多少
<gadget id="calculator">18 * 4</gadget>
<output>72</output>

<gadget id="calculator">16 * 4</gadget>
<output>64</output>

<gadget id="calculator">72 - 64</gadget>
<output>8</output>

<result>8</result>