(x,y)
x is left right
y is up down
move up c units means add c to y
move down c units means minus c from y
move right c units means add c to x
move left c units means minus c from x
(5,2)
(x,y)
x=5, y=2
move 3 left
minus 3 from 5 to get 2
move 2 up
add 2 to 2 to get 4
(2,4)
