A square and a rectangle have the same perimeter, and the sides of the square are 10 cm long. If the length of the rectangle is 12 cm, what is the width of the rectangle in cm?
一个正方形和一个长方形的周长相等，正方形边长10厘米．如果长方形的长是12厘米，长方形的宽是多少厘米？
<gadget id="calculator">10 * 4</gadget>
<output>40</output>

<gadget id="calculator">40 / 2</gadget>
<output>20</output>

<gadget id="calculator">20 - 12</gadget>
<output>8</output>

<result>8</result>