It takes 36 shells to make a small hedgehog, and 12 shells are 9 times less than the small hedgehog to make a big hedgehog. How many shells does it take to make a big hedgehog?
做一个小刺猬用36个贝壳，做一个大刺猬用的贝壳数比小刺猬的9倍少12个．做一个大刺猬用多少个贝壳．
<gadget id="calculator">36 * 9</gadget>
<output>324</output>

<gadget id="calculator">324 - 12</gadget>
<output>312</output>

<result>312</result>