The three-day sales of Tongxin toy store are 720 yuan, 700 yuan, and 680 yuan respectively. According to this calculation, how much is the 30-day sales of this toy store?
童心玩具店3天的销售额分别是720元、700元、680元，照这样计算，这个玩具店30天的销售额是多少元．
<gadget id="calculator">720 + 700 + 680</gadget>
<output>2_100</output>

<gadget id="calculator">2_100 / 3</gadget>
<output>700</output>

<gadget id="calculator">700 * 30</gadget>
<output>21_000</output>

<result>21_000</result>