The blackboard in the classroom is 3.2 meters long and 1.5 meters wide. Lace should be around the blackboard. How long is the lace?
教室的黑板长3.2米，宽1.5米，要在黑板的周边围上花边，花边长多少米？
<gadget id="calculator">3.2 + 1.5</gadget>
<output>4.7</output>

<gadget id="calculator">4.7 * 2</gadget>
<output>9.4</output>

<result>9.4</result>