I am flat and round, often covered in tomato sauce and cheese, and usually cut into triangular slices. What am I?

I have many windows and take you where you want to go. A number is on my back. Solve the riddle → What has many teeth but no mouth? Solve the riddle → I keep your neck warm when it's cold outside. What am I? Solve the riddle → I have many pieces that need to be put together to form a picture. What am I? Solve the riddle → I can be found on clothes and remote controls. You can press me. What am I? Solve the riddle →