An electric classroom needs to be paved with square bricks, and the square bricks with a side length of 3 decimeters need 960 yuan. If you use square bricks with a side length of 2 decimeters instead, how many pieces are needed? (answer with ratio)
一个电教室要用方砖铺地，用边长是3分米的方砖铺，需要960块．如果改用边长是2分米的方砖铺，需要多少块？(用比例解答)
<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>