A rectangle has a perimeter of 22 decimeters and a length of 7 decimeters. What is its width?
一个长方形，周长是22分米，长7分米，宽是长的多少．
<gadget id="calculator">22 / 2</gadget>
<output>11</output>

<gadget id="calculator">11 - 7</gadget>
<output>4</output>

<gadget id="calculator">4 / 7</gadget>
<output>4/7 = around 0.571429</output>

<result>4/7 = around 0.571429</result>