In terms of charge:

* An electron has a charge of -1.

* A proton has a charge of +1.

* When you combine an electron and a proton, their charges cancel out, resulting in a neutral particle. This is the fundamental basis of an atom.

In terms of particle physics:

* An electron is a fundamental particle, meaning it's not made of anything smaller.

* Adding a proton to an electron doesn't create a new particle, but rather forms a hydrogen atom.

In other contexts:

* "Plus" can also be used to represent addition. However, adding an electron to something else (like a material) is not a simple addition. It depends on the material and the specific conditions.

To get a more precise answer, please clarify what you mean by "plus."