The temperature measured by a small meteorological team in Helan at 4 o'clock, 8 o'clock, 12 o'clock and 2 o'clock in a day is 15°C, 20°C, 28°C, and 19°C respectively. What is the average temperature of this day?
贺兰一小气象小组在一天中的4时、8时、12时、2时测得气温分别是15℃、20℃、28℃、19℃，这天平均气温是多少℃．
<gadget id="calculator">15 + 20 + 28 + 19</gadget>
<output>82</output>

<gadget id="calculator">82 / 4</gadget>
<output>41/2 = around 20.5</output>

<result>41/2 = around 20.5</result>