There are four numbers whose average is 3, if one of the numbers 1 is changed to 9, what is the average of them?
有四个数，它们的平均数是3，把其中一个数1改为9，那么它们的平均数变成了多少．
<gadget id="calculator">9 - 1</gadget>
<output>8</output>

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

<gadget id="calculator">3 + 2</gadget>
<output>5</output>

<result>5</result>