There were several tons of chemical fertilizers in the warehouse, half of them were taken out on the first day, more than 30 tons, the remaining half was taken out on the second time, less than 100 tons, and 150 tons were taken out on the third time, and 70 tons were left in the end. How much was this batch of chemical fertilizers? Ton?
仓库里原有化肥若干吨，第一天取出全部的一半多30吨，第二次取出余下的一半少100吨，第三次取出150吨，最后还剩下70吨，这批化肥原有多少吨？
<gadget id="calculator">70 - 100</gadget>
<output>-30</output>

<gadget id="calculator">150 + (-30)</gadget>
<output>120</output>

<gadget id="calculator">120 * 2</gadget>
<output>240</output>

<gadget id="calculator">240 + 30</gadget>
<output>270</output>

<gadget id="calculator">270 * 2</gadget>
<output>540</output>

<result>540</result>