Let's tackle subtraction first. Subtraction in hexadecimal works similar to subtraction in decimal. Let's do a pair of decimal problems and see if we can parallel the solution method in hex. Suppose we want to subtract 1586 - 243 (in decimal).
Refraction of Light Rays. the bending or deflection of light rays as they pass through the various media of the eye that include the conjuctiva, cornea, aqueous humor, lens, and vitreous body.
Light rays enter the front of your eye through the clear cornea and lens. It is very important that both the cornea and lens are clear as this allows the light to pass directly through the front of your eye to the retina. The cornea and lens bend light so that it can focus on the retina at the back of your eye.