The school playground is 120m long and 80m wide. Put colorful flags around the playground (all four corners must be inserted), and the interval between two adjacent colored flags is 4m. How many flags are there in total?
学校操场长120m，宽80m．在操场四周插上彩旗(四个角上都要插)，每相邻两面彩旗的间隔是4m．一共要插多少面彩旗？
<gadget id="calculator">120 + 80</gadget>
<output>200</output>

<gadget id="calculator">200 * 2</gadget>
<output>400</output>

<gadget id="calculator">400 / 4</gadget>
<output>100</output>

<result>100</result>