A barrel of pesticides, pour 160 grams into the barrel for the first time, pour out (1/8) of the barrel for the second time, and pour out 300 grams for the third time, and there are 120 grams left in the barrel. How many grams of pesticides are there in the barrel?
一桶农药，第一次倒进160克，第二次倒出桶中的(1/8)，第三次倒出300克，桶中还剩下120克，原来桶中有多少克农药．
<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">160 * (1/8)</gadget>
<output>20</output>

<gadget id="calculator">120 - 20</gadget>
<output>100</output>

<gadget id="calculator">160 + 300 + 100</gadget>
<output>560</output>

<gadget id="calculator">1 - (1/8)</gadget>
<output>7/8 = around 0.875</output>

<gadget id="calculator">560 / (7/8)</gadget>
<output>640</output>

<result>640</result>