Type Effectiveness against Magikarp
This are the new efficiencies in Pokémon GO (see here):
- Effectiv: 1.25 => 1.40
- Not effectiv: 0.80 => 0.714
- Imune: 0.80 => 0.51
- STAB: 1.25 => 1.20
The type strength and weaknesses still stack multiplicatively in Pokémon GO. So the values above are already the stacked damage multiplier.
Poison is weak against ground and steel is imune against poison. So the final damage multiplier for poison against steelix will be 0.714 x 0.51 = 0.364.
Exception: If a move is effectiv against the first type and not effectiv against the second type it would be 1.4 x 0.714 = 0.9996. But above we are showing it as 1.
The moves highlighted in green have the same type as the Pokémon and deal 20% more damage. (Same Type Attack Bonus)