There were $8\times2=16$ slices. $13+1=14$ slices of pizza were ate, so there were $16-14=2$ slices left. 
Vera invited $$13$$ guests to her birthday party. She had $$2$$ pizzas, and each of them was cut into $$8$$ slices. Each person at the party ate one slice of pizza. How many slices of pizza were left over? (2015 Math Kangaroo Problem, Level 1-2, Question \#14) 

1. $$5$$ 
2. $$4$$ 
3. $$3$$ 
4. $$2$$ 
5. $$1$$ 