From 8:00 to 12:00, I sprayed a total of 840 apple trees. How many trees are sprayed per hour on average?
从8时到12时，我一共给840棵苹果树喷了药水，平均每小时喷多少棵？
<gadget id="calculator">840 / 8</gadget>
<output>105</output>

<result>105</result>