If two squares with a perimeter of 16 cm are put together to form a rectangle, the perimeter is reduced by how many centimeters.
把两个周长是16厘米的正方形拼成一个长方形，周长减少了多少厘米．
<gadget id="calculator">16 / 4</gadget>
<output>4</output>

<gadget id="calculator">4 * 2</gadget>
<output>8</output>

<result>8</result>