A monkey picked a bunch of peaches, on the first day it ate (1/7) of the peaches; on the second day it ate (1/6) of the remaining peaches; on the third day it ate (1/6) of the remaining peaches 1/5); on the fourth day it ate (1/4) of the remaining peaches; on the fifth day it ate (1/3) of the remaining peaches; on the sixth day it ate (1/2) of the remaining peaches. At this time, there are still 12 peaches left, so what is the total number of peaches eaten by the monkeys in the previous three days?
一只猴子摘了一堆桃子，第一天它吃了这堆桃子的(1/7)；第二天它吃了余下桃子的(1/6)；第三天它吃了余下桃子的(1/5)；第四天它吃了余下桃子的(1/4)；第五天它吃了余下桃子的(1/3)；第六天它吃了余下桃子的(1/2)．这时还剩下12只桃子，那么前三天猴子所吃桃子的总数是多少．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 - (1/2)</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

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

<gadget id="calculator">1 - (1/4)</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">1 - (1/6)</gadget>
<output>5/6 = around 0.833333</output>

<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">1 - (1/7)</gadget>
<output>6/7 = around 0.857143</output>

<gadget id="calculator">12 / (1/2) / (2/3) / (3/4) / (4/5) / (5/6) / (6/7)</gadget>
<output>84</output>

<gadget id="calculator">84 * (1/7)</gadget>
<output>12</output>

<gadget id="calculator">84 - 12</gadget>
<output>72</output>

<gadget id="calculator">72 * (1/6)</gadget>
<output>12</output>

<gadget id="calculator">84 - 12 - 12</gadget>
<output>60</output>

<gadget id="calculator">60 * (1/5) * 3</gadget>
<output>36</output>

<result>36</result>