An eagle-eyed motorist clocked the double mistake at the Evans Halshaw dealership off White Rose Way - where a sign for "servicing" was spelled "servicning" while another notice on a van reduced in price claimed it would save the buyer £9,890 - when the deal offered actually saves £11,860.
The notice, plastered on the side of a white van, lists the vehicle as originally being priced at £25,050, reduced to £13,190 and "saving £9,890" - when the actual saving is £11,860 - a difference of £1,970.
Bobby Ziyaei who spotted the mistakes at the Renault dealer said: "Really bad spelling and bad maths on the van too.
"I drove round Ten Pound Walk and back just to make sure it wasn't me who read it wrong!"
We have contacted Evans Halshaw for comment.