There are 4 walnut trees, each yielding 78 kg, 69 kg, 55 kg, and 64 kg, respectively. How many kg of walnuts does each tree produce on average?
有4棵核桃树每棵产量分别是78千克，69千克，55千克，64千克，平均每棵产多少千克核桃．
<gadget id="calculator">78 + 69 + 55 + 64</gadget>
<output>266</output>

<gadget id="calculator">266 / 4</gadget>
<output>133/2 = around 66.5</output>

<result>133/2 = around 66.5</result>