A classroom is 8.4 meters long and 7.2 meters wide. If square tiles with a side length of 6 decimeters are used to pave the floor, how many tiles are needed at least?
一间教室长8.4米，宽7.2米，如果用边长是6分米的正方形瓷砖铺地，至少要多少块瓷砖？
<gadget id="calculator">8.4 * 7.2</gadget>
<output>60.48</output>

<gadget id="calculator">6 / 10</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">(3/5) * (3/5)</gadget>
<output>9/25 = around 0.36</output>

<gadget id="calculator">60.48 / (9/25)</gadget>
<output>168</output>

<result>168</result>