There are 21 potted flowers placed on one side of the playground, and the interval between them is 1 meter. Now the interval is changed to 4 meters. How many potted flowers need to be placed?
操场的一侧摆了21盆花，它们的间隔是1米，现在要改为间隔4米，需要摆几盆花？
<gadget id="calculator">21 - 1</gadget>
<output>20</output>

<gadget id="calculator">1 * 20</gadget>
<output>20</output>

<gadget id="calculator">20 / 4</gadget>
<output>5</output>

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

<result>6</result>