A square field is paved with rectangular stone slabs 1.5 meters long and 1.2 meters wide. How many stone slabs are needed at least?
用长1.5米，宽1.2米的长方形石板铺成一个正方形场地，最少要多少块石板？
<gadget id="calculator">60 / 15</gadget>
<output>4</output>

<gadget id="calculator">60 / 12</gadget>
<output>5</output>

<gadget id="calculator">4 * 5</gadget>
<output>20</output>

<result>20</result>