Ding Ding’s house plans to lay upper bricks on the floor of the living room with a length of 6 meters and a width of 4 meters. There are two kinds of square bricks, one is 5 yuan each with a side length of 2 decimeters, and the other is 1 decimeter each. Block 3 yuan. Which square brick is cheaper to choose? How many bricks of this kind do you need?
丁丁家准备在长6米，宽4米的客厅地面上铺上方砖，有两种方砖，一种是边长2分米的每块5元，另一种是边长1分米的每块3元．选择哪种方砖便宜？需要这种方砖多少块？
<gadget id="calculator">2 * 2</gadget>
<output>4</output>

<gadget id="calculator">1_800 / 4</gadget>
<output>450</output>

<result>450</result>