The area of a classroom is 45.36 square meters, and the floor is paved with square tiles with a side length of 0.9 meters. How many pieces of this kind of tiles are needed in total?
一间教室的面积是45.36平方米，用边长是0.9米的正方形瓷砖铺地，共需这种瓷砖多少块？
<gadget id="calculator">0.9 * 0.9</gadget>
<output>0.81</output>

<gadget id="calculator">45.36 / 0.81</gadget>
<output>56</output>

<result>56</result>