The kindergarten teacher distributes biscuits to 12 children. Each of them gives 3 yuan and there is some left over, but 4 yuan is not enough. It is known that there are as many leftovers as there are not enough. How many biscuits are there in total?
幼儿园老师给12个小朋友发饼干，每人发3块还剩下一些，每人发4块又不够，已知剩下的和不够的同样多，问一共有多少块饼干？
<gadget id="calculator">12 * 3</gadget>
<output>36</output>

<gadget id="calculator">12 * 4</gadget>
<output>48</output>

<gadget id="calculator">48 - 36</gadget>
<output>12</output>

<gadget id="calculator">12 / 2</gadget>
<output>6</output>

<gadget id="calculator">36 + 6</gadget>
<output>42</output>

<result>42</result>