The school bought a batch of soy milk, the lower grades used it (2/5), and the middle grades used 25% of the original total. Senior grade used 630 bottles. How many bottles of soy milk are in this batch?
学校进了一批豆奶，低年级用了它的(2/5)，中年级用了原来总量的25%．高年级用了630瓶．这批豆奶有多少瓶？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (2/5) - (1/4)</gadget>
<output>7/20 = around 0.35</output>

<gadget id="calculator">630 / (7/20)</gadget>
<output>1_800</output>

<result>1_800</result>