There is a batch of biscuits on the shelves of Aijia Supermarket. After they are sold (2/3), the salesperson adds another 18 packs. At this time, the number of packs of biscuits on the shelf is exactly 12 packs less than the original (5/6). How many packages of biscuits are there on the shelf?
爱家超市货架上有一批饼干，卖出(2/3)后，营业员又加进了18包，这时货架上饼干的包数恰好比原来的(5/6)少12包．货架上原有饼干多少包？
<gadget id="calculator">18 + 12</gadget>
<output>30</output>

<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">5 / 6</gadget>
<output>5/6 = around 0.833333</output>

<gadget id="calculator">(5/6) - 1</gadget>
<output>-1/6 = around -0.166667</output>

<gadget id="calculator">(2/3) + (-1/6)</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">30 / (1/2)</gadget>
<output>60</output>

<result>60</result>