Algebra Rules and Formulas

PEMDAS: Order of Operations. Parenthesis, exponent, multiply, divide, add and subtract.

Commutative: a + b = b + a ; a x b = b x a
Associative: (a + b) + c = a + (b + c);  a(bc) = (ab)c
Distributive: a(b+c) = ab + bc
Identity: 0+ a = a; 1 x a = a
Inverse: a x 1/a = 1; a/b x b/a = 1
Negativity (Add): 1 - (-1) = 1 + 1
Negativity (Multiply): 1 x -1 = -1; -1 x -1 = 1
Zero: a/0 is undefined
Fractions: a/a = 1; 

Adding Fractions: a/c + b/c = (a +b) / c
Multiplying Fractions: a/b x c/d = ac/bd
Exponents: a^0 = 1; a^1 = a; a^2 = a x a;  a^3 = a x a x a
Area, Rectangle: base x height

Area Triangle: 1/2 base x height
Volume of a box: length x width x height

1000 millimeter = 100 centimeter = 1 meter; 1000 meters - 1 Kilometer
36 inches = 3 feet = 1 yard; 1 mile = 5,280 feet
2.2 pounds = 1 kilogram;
approximately: 60 mph = 88 feet per second; 100 Km per hour = 28 meters per second
A commercial jet travels at about 550 mph
Diameter of the earth / sun:  8,000 / 870,000. The sun is about 100 times bigger than the earth.