Insert 7 numbers between 8 and 40 so that they form arithmetic progressions with these two numbers. What is the tolerance of this arithmetic sequence.
在8与40之间插入7个数，使它们同这两个数成等差数列．这个等差数列的公差是多少．
<gadget id="calculator">40 - 8</gadget>
<output>32</output>

<gadget id="calculator">2 + 7</gadget>
<output>9</output>

<gadget id="calculator">9 - 1</gadget>
<output>8</output>

<gadget id="calculator">32 / 8</gadget>
<output>4</output>

<result>4</result>