Four consecutive natural numbers, the largest being 72, what is the average of these four numbers.
四个连续自然数，最大的是72，这四个数的平均数是多少．
<gadget id="calculator">72 - 3</gadget>
<output>69</output>

<gadget id="calculator">72 - 2</gadget>
<output>70</output>

<gadget id="calculator">72 - 1</gadget>
<output>71</output>

<gadget id="calculator">69 + 70 + 71 + 72</gadget>
<output>282</output>

<gadget id="calculator">282 / 4</gadget>
<output>141/2 = around 70.5</output>

<result>141/2 = around 70.5</result>