mathinschool.com
numbers and algebraic expressions
logic, sets, intervals
absolute value
function and its properties
linear function
quadratic function
polynomials
rational function
exponential function
logarithm
number sequences
limits of sequences and functions
derivative and integral of functions
trigonometry
plane geometry
analytic geometry
solid geometry
combinatorics
probability
elements of statistics
kropki game

The direction of vector is where arrowhead of vector points. Collinear vectors lie on the same line or on parallel lines. Vectors with the same direction. Up, right, down and left direction of vector. Collinear vectors with opposite directions. Non-collinear vectors. Two vectors are equal if they have the same direction and magnitude. Opposite vectors have the same magnitude but opposite directions.