Deceleration, or decrease in speed, can be calculated using multiple different formulas, depending on the available parameters. Some deceleration formulas include a = (v  u)/t, and a = (v^2  u^2) / (2s).
One formula to calculate deceleration is a = (v  u)/t, where a is the deceleration, v is the final velocity, u is initial velocity and t is the time taken. If distance covered is known but time passed is not known, a second formula that can be used is a = (v^2  u^2) / (2s), where a is the deceleration, v is final velocity, u is initial velocity and s is the distance covered. The deceleration formulas calculate the rate of decrease in overall speed. Deceleration is typically measured in meters per second^2, or other distance per time unit squared units.
(Final Velocity Initial Velocity)/ Time It's the same as for acceleration.
http://wiki.answers.com/Q/What_is_the_formula_to_c...

1. Subtract the ending speed from the starting speed. 2. Convert the speed difference to units of speed that are compatible with the acceleration you will calculate. Acceleration
http://www.ehow.com/how_6081657_calculatedecelera...

The formula for it is Deceleration=original velocityfinal velocity)/Time.
http://www.chacha.com/question/whatistheformula...

1. Get your pay off odds eg 2 to 1 in x is the odds against (2) and y is the odds of it happening (1) then do B = 1 / Y * X. The percentage of chance you think you have of winning
http://www.wikihow.com/CalculatetheKellyFormula
