1. Let me in.
2. Let me into.
3. Let me in the group.
3-1. Let me be in the group.
4. Let me into the group.
4-2. Let me go into the group.
5. Let me out.
6. Let me out of the room.
7. Let me be out of the room.
7-1. Let me go out of the room.
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Which ones are grammatically correct? Which ones are commonly used? Thank you.
2 is incorrect.
7 is grammatically correct, but not used much.
All the others are fine.