classroom should be paved with square bricks. Using square bricks with a side length of 3 decimeters requires 960 pieces. If the square bricks with a side length of 2 decimeters are used instead, how many pieces are needed? (Solve with ratio)
一间教室要用方砖铺地．用边长是3分米的正方形方砖，需要960块，如果改用边长为2分米的正方形方砖，需要多少块？(用比例解)
<gadget id="calculator">3 * 3 * 960</gadget>
<output>8_640</output>

<gadget id="calculator">2 * 2</gadget>
<output>4</output>

<gadget id="calculator">8_640 / 4</gadget>
<output>2_160</output>

<result>2_160</result>