There is a box of apples, first take out all (3/4), and then put back 10. At this time, the number of apples in the box is just taken out (1/2), how many original apples are in the box?
有一箱苹果，先取出全部的(3/4)，再放回10个，这时箱里的苹果个数正好是取出的(1/2)，箱里原有苹果多少个？
<gadget id="calculator">2 + 1</gadget>
<output>3</output>

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

<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">1 - (3/4)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(1/3) - (1/4)</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">10 / (1/12)</gadget>
<output>120</output>

<result>120</result>