rectangular brick is 42cm long and 24cm wide. At least how many bricks are needed to pave a square with this kind of bricks?
一块长方形砖长42cm，宽24cm．用这种砖铺成一块正方形地至少要多少块？
<gadget id="calculator">168 / 42</gadget>
<output>4</output>

<gadget id="calculator">168 / 24</gadget>
<output>7</output>

<gadget id="calculator">4 * 7</gadget>
<output>28</output>

<result>28</result>