A room is just covered with 80 square bricks of 90 square decimeters. If you use square bricks with a side length of 3 decimeters, how many pieces are needed?
一间房用90平方分米的方砖80块正好铺满．如果用边长3分米的方砖，需要多少块？
<gadget id="calculator">3 * 3</gadget>
<output>9</output>

<gadget id="calculator">90 / 9</gadget>
<output>10</output>

<gadget id="calculator">80 * 10</gadget>
<output>800</output>

<result>800</result>