HP calculation: (2*BaseStat+IV+EV/4*Level)/100+Level+10
Other Stats calculation: ((2*BaseStat+IV+EV/4*Level)/100+5)*NatureBoost
Damage Calculation: (((2*Attacker's Level)+10)/250*(Attacker's Attack or Special Attack/Defender's Defence or Special Defence)+2)*(All other modifiers)
Experience Earned (Gen 2, 3, and 4): (Base Experience of the defeated Pokémon)*(Level of the defeated Pokémon)*(All other modifiers)/(7*Number of Pokémon who fought the battle)
Pokémon is not complicated at all
Other Stats calculation: ((2*BaseStat+IV+EV/4*Level)/100+5)*NatureBoost
Damage Calculation: (((2*Attacker's Level)+10)/250*(Attacker's Attack or Special Attack/Defender's Defence or Special Defence)+2)*(All other modifiers)
Experience Earned (Gen 2, 3, and 4): (Base Experience of the defeated Pokémon)*(Level of the defeated Pokémon)*(All other modifiers)/(7*Number of Pokémon who fought the battle)
Pokémon is not complicated at all