Vectors
2 + 2 does not always equal 4 when the problem is translated into a 2 or 3 dimensional space. Vectors are quantities that have both magnitude (size) and direction. This branch of maths is fundamental to physics and engineering to represent physical quantities that have a direction.
Use these measurement worksheets to improve your skills in these areas.
The University of Colorado has some useful vector simulations, so come back and have a look at those once you've used the worksheets below.