A box of beads, take out (1/5) and 4 of the total number for the first time, take out the remaining (1/4) and 3 for the second time, and take out the remaining (1/3) and 2 for the third time, Take out the remaining (1/2) and another one for the fourth time, and there is still one in the box at this time. How many beads were there originally in the box?
一盒珠子，第一次取出总数的(1/5)又4个，第二次取出余下的(1/4)又3个，第三次取出又余下的(1/3)又2个，第四次取出再余下的(1/2)又1个，这时盒子里还有1个．盒子里原有珠子多少个？
<gadget id="calculator">1 + 1</gadget>
<output>2</output>

<gadget id="calculator">2 * 2</gadget>
<output>4</output>

<gadget id="calculator">4 + 2</gadget>
<output>6</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">6 / (2/3)</gadget>
<output>9</output>

<gadget id="calculator">9 + 3</gadget>
<output>12</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">12 / (3/4)</gadget>
<output>16</output>

<gadget id="calculator">16 + 4</gadget>
<output>20</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">20 / (4/5)</gadget>
<output>25</output>

<result>25</result>