how to dervie equations of motion in a easy way?

acceleration = rate of change of velocity

a = (v - u) / t

or, at = v - u

or, v = u + at ( 1st eqn of motion)

Distance = average velocity x time

or     s = [( v + u ) /2 ] x t

or,    s =  [(u + at + u)/2] x t

or ,    s = ut + at²/ t ( 2nd eqn of motion)

Also,    s = average velocity x t

or,   s = [(v + u)/ 2]  x [(v - u)/a]

or,   s  = (v² - u²⁾ / 2a

or,  v² - u² = 2as ( 3rd eqn of motion)