to stack up

[Offroad]

Dear teachers

Do these sentences read well?

They are getting ready to stack up his skills with their oponents.
They are preparing themselves to stack up their abilities against others.
They are going to stack up their knowledge to their competitors.

Many thanks

[Rover_KE]

No, they do not read well.

I don't understand the meaning of any of them.

Rover

[billmcd]

Dear teachers

Do these sentences read well?

They are getting ready to stack up his skills with their oponents. OK but I would use "against"
They are preparing themselves to stack up their abilities against others. OK
They are going to stack up their knowledge to their competitors. "against"

Many thanks

And I would use "match" in place of "stack up".

[Offroad]

How about these?

They are getting ready to stack up his skills against those of their oponents.
They are getting ready to stack up his skills against their oponents's.

[billmcd]

How about these?

They are getting ready to stack up his skills against those of their oponents.
They are getting ready to stack up his skills against their oponents's.

OK but no apostrophe.