The total length from one end of the playground to the other end is 120 meters, and a small red flag is inserted every 4 meters. Now it is changed to a small red flag every 6 meters. How many small red flags are there that do not need to be pulled out?
从运动场一端起到另一端全长120米，每隔4米插一面小红旗，现在要改成每隔6米插一面小红旗，问可以不必拔出来的小红旗有多少面？
<gadget id="calculator">120 / 12</gadget>
<output>10</output>

<gadget id="calculator">10 + 1</gadget>
<output>11</output>

<result>11</result>