The students plant trees on the side of a playground that is 100 meters long and 80 meters wide. There are trees planted at the four vertices. One tree is planted every 10 meters on the long side, and one tree is planted every 8 meters on the wide side. How many trees were planted in total?
同学们在一个长100米，宽80米的操场边植树，四个顶点都种有一棵树，长边每隔10米种一棵，宽边每隔8米种一棵．一共种树多少棵？
<gadget id="calculator">100 / 10</gadget>
<output>10</output>

<gadget id="calculator">80 / 8</gadget>
<output>10</output>

<gadget id="calculator">10 + 10</gadget>
<output>20</output>

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

<result>40</result>