To pave a field, 2400 square bricks with a side length of 3dm are needed. How many bricks should be used to pave with square bricks with a side length of 2dm? (Solution by proportional method)
铺一块地，用边长3dm的方砖要2400块．改用边长2dm的方砖铺，要用多少块砖？(用比例方法解)
<gadget id="calculator">2_400 * 3 * 3</gadget>
<output>21_600</output>

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

<gadget id="calculator">21_600 / 4</gadget>
<output>5_400</output>

<result>5_400</result>