A corridor is 20 meters long, and a potted flower is placed every 4 meters, both ends must be placed. How many potted flowers do you need in total?
一条走廊长20米，每隔4米放一盆花，两端都要放．一共需要放多少盆花．
<gadget id="calculator">20 / 4</gadget>
<output>5</output>

<gadget id="calculator">5 + 1</gadget>
<output>6</output>

<result>6</result>