## Players usually see all dice that they roll

The [introduction][1] to the basic rules says this simply, and even gives an example:
> **Players roll dice** to resolve whether their attacks hit or miss or whether their adventurers can scale a cliff, roll away from the strike of a magical lightning bolt, or pull off some other dangerous task. Anything is possible, but the dice make some outcomes more probable than others.

> [...]

> > DM: Make an Intelligence check.

> > Phillip: Does my Investigation skill apply?

> > DM: Sure!

> > **Phillip (rolling a d20): Ugh. Seven.**

### DMs may want to roll their own die secretly

Many DMs will hide their own rolls, and the DMG even makes suggestions for rolling for the player in secret in some situations. 

  [1]: https://www.dndbeyond.com/sources/basic-rules/introduction