RockSteel
Rock/Steel weaknesses
Rock/Steel is weak to Fighting, Ground and Water, and takes 4× from Fighting and Ground.
When Rock/Steel 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, Fighting deals 2× × 2× = 4×.