A display device capable of improving image quality is provided. The display device is provided with an adder circuit in and outside a display region, and the adder circuit has a function of adding a plurality of data supplied from a source driver together. Components of the adder circuit are divided and partly arranged in the display region. Thus, limitation on the size of the component included in the adder circuit can be eased, and data addition can be performed efficiently. In addition, by providing other components included in the adder circuit outside the display region, the number of wirings in the display region can be reduced and the aperture ratio of the pixel can be increased.