A rectangular flower bed is 50 meters long and 40 meters wide. If you want to count the trees every 5 meters around the flower bed, how many trees will be planted in total?
一个长方形花坛，长50米，宽40米，若要在花坛周围每隔5米在一棵数，共栽多少棵？
<gadget id="calculator">50 + 40</gadget>
<output>90</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">90 * (2/5)</gadget>
<output>36</output>

<result>36</result>