It takes 1,800 pieces to pave a square with square bricks with a side length of 6 decimeters. How many pieces are needed if square bricks with a side length of 9 decimeters are used instead?
用边长6分米的方砖铺设一个广场需1800块，如果改用边长9分米的方砖需要多少块？
<gadget id="calculator">6 * 6 * 1_800</gadget>
<output>64_800</output>

<gadget id="calculator">9 * 9</gadget>
<output>81</output>

<gadget id="calculator">64_800 / 81</gadget>
<output>800</output>

<result>800</result>