In an process, the system releases heat that is absorbed by the ; in an endothermic process, the absorbs heat from the

In an exothermic process, the system releases heat that is absorbed by the surrounding; in an endothermic process, the system absorbs heat from the surrounding. 

The diagrammatic representation of endo and exothermic reaction is attached for quick reference.  From the diagram, it can be seen that during exothermic reaction, product formed is stable as compared to reactant, while in case of endothermic reaction reactant is more stable than product. 

So what you would do is go through and add 3 teaspoons(tsp) 6 times because of the 6 tablespoons(tbsp). which will give you an answer of 18. another way is to multiply 3x6=18.