The store purchased 520 digital video cameras, which is 80 less than twice the number of digital cameras purchased. How many digital cameras are there? Solve the equation.
商店购进520台数码摄像机，比购进的数码照相机的2倍少80台，数码照相机有多少台？用方程解．
<gadget id="calculator">80 + 520</gadget>
<output>600</output>

<gadget id="calculator">600 / 2</gadget>
<output>300</output>

<result>300</result>