brick has a base area of 300cm**2 and a height of 4cm. Now, 1500 bricks of this kind are used to build a wall. How much space does this wall occupy at least?
一块砖的底面积是300cm**2，高是4cm．现在砌一面墙用了这种砖1500块，这面墙至少占多大的空间？
<gadget id="calculator">1_500 / 1_000_000</gadget>
<output>3/2_000 = around 0.0015</output>

<gadget id="calculator">300 * 4 * (3/2_000)</gadget>
<output>9/5 = around 1.8</output>

<result>9/5 = around 1.8</result>