The Palace of Culture held a famous painting exhibition. There were 340 people visiting the exhibition in the morning. In the afternoon, the number of visitors was twice the number in the morning. In the evening, the number of visitors was half that in the morning. How many people visited the exhibition on this day?
文化宫举行名画展览，上午有340人参观展览，下午参观的人数是上午参观人数的2倍，晚上参观人数是上午的一半，这一天共有多少人参观展览？
<gadget id="calculator">340 * 2</gadget>
<output>680</output>

<gadget id="calculator">340 / 2</gadget>
<output>170</output>

<gadget id="calculator">340 + 680 + 170</gadget>
<output>1_190</output>

<result>1_190</result>