An operation method of a display device with high visibility is to be provided. The display device is an electronic device including a first display element, a second display element, an optical sensor, and a gain calculation circuit. In the electronic device, the illuminance of external light is obtained with the optical sensor, and depending on the illuminance, images displayed using the first display element and the second display element are corrected. The gain calculation circuit obtains the illuminance and calculates a gain value depending on the illuminance. In particular, the gain value is calculated for each of the first display element and the second display element. Furthermore, the gain calculation circuit performs dimming and toning on image data displayed using the first display element and the second display element by multiplying the image data by the gain values or values corresponding to the gain values.