GroundRock
Ground/Rock weaknesses
Ground/Rock is weak to Water, Grass, Ice, Fighting, Ground and Steel, and takes 4× from Water and Grass.
When Ground/Rock Pokémon are hit
4×Hits hardest
2×Super effective
½×Not very effective
¼×Barely scratches it
0×No effect
Its two types separately
Multiply the two to get the result. For example, Water deals 2× × 2× = 4×.