How many circles with a diameter of 3 cm can be cut from a rectangular piece of paper with a length of 12 cm and a width of 6 cm.
在一张长12厘米，宽6厘米的长方形纸中，最多可以剪多少个直径为3厘米的圆．
<gadget id="calculator">12 / 3</gadget>
<output>4</output>

<gadget id="calculator">6 / 3</gadget>
<output>2</output>

<gadget id="calculator">4 * 2</gadget>
<output>8</output>

<result>8</result>