How the RGB color values are written?

Answer 1

Red is #FF0000 in hex and 255,0,0 in decimal
Green is #00FF00 in hex and 0,255,0 in dec
Blue is #0000FF in hex and 0,0,255 in dec

Answer 2

RedGreenBlue (0/../255,0/.../255,0/.../255)
An RGB color value is specified with: rgb(red, green, blue). Each parameter (red, green, and blue) defines the intensity of the color and can be an integer between 0 and 255 or a percentage value (from 0% to 100%). w3