An arithmetic device and an electronic device having small power consumption is provided. An arithmetic device and an electronic device capable of high-speed operation is provided. An arithmetic device and an electronic device capable of suppressing heat generation is provided. The arithmetic device includes a first arithmetic portion and a second arithmetic portion. The first arithmetic portion includes a first CPU core and a second CPU core. The second arithmetic portion includes a first GPU core and a second GPU core. The CPU cores each have a power gating function and each include a first data retention circuit electrically connected to a flip-flop. The first GPU core includes a second data retention circuit capable of retaining an analog value and reading out the analog value as digital data of two or more bits. The second GPU core includes a third data retention circuit capable of retaining a digital value and reading out the digital value as digital data of one bit. The first to third data retention circuits each include a transistor including an oxide semiconductor and a capacitor.