The heights of the three students in Class 3 and 1 are 138cm, 140cm, and 136cm respectively. What is their average height in cm?
三1班3名同学的身高分别是138cm、140cm、136cm，他们的平均身高是多少cm
<gadget id="calculator">138 + 140 + 136</gadget>
<output>414</output>

<gadget id="calculator">414 / 3</gadget>
<output>138</output>

<result>138</result>