# Quant Basics – Revision

A few definitions/ concepts/ formulae you should revise before taking your first practice GMAT:

- Integers: Numbers, such as -1, 0, 1, 2, and 3, that have no decimal (fractional) part. Integers include the counting numbers (1, 2, 3, …), their negative counterparts (-1, -2, -3, …), and 0.
- Factors: Positive integers that divide evenly into an integer. Factors are equal to or smaller than the integer in question. 12 is a factor of 12, as are 1, 2, 3, 4, and 6.
- Prime Numbers: A positive integer with exactly two factors: 1 and itself.
- Odd & Even Numbers: Any number divisible by 2 is even and not divisible by 2 is odd.
- Equations:
- a
^{2}– b^{2}= (a + b) * (a – b) - (a + b)
^{2}= a^{2}+ 2ab + b^{2} - (a – b)
^{2}= a^{2}– 2ab + b^{2}

- a
- Geometry
- Interior angles of a triangle add up to 180 degrees
- Right triangle: A triangle that includes a 90 degrees angle
- Area of a triangle = 1/2 x base x height
- Pythagoras theorem: p
^{2}+ b^{2}= h^{2}(used to calculate sides of a right triangle; h: longest side – side opposite the right angle) - Square: All 4 sides equal, all 4 angles 90 degrees; area of square = side
^{2} - Area of rectangle = length x width
- Volume of a cume = side
^{3} - Volume of a rectangular solid = length x width x height
- Area of a circle = pi x r
^{2}(Where pi is a constant ~3.14, r is the radius of the circle) - Distance = Rate x Time (rate, or speed, measured in units of distance per unit of time)