There can be many benefits and down sides to this, in return for helping these countries you gain an ally. Although you have to spend your own money. All in all it is worth it in the end because you have another country you can trust.
Community
Geography
Equality
I prefer flash cards "since i'm a visual", but you could always ask a friend to help you out to study.
Multiply 30 x .2 when dealing with percentages of 100 you turn it into decimal form and multiply by the whole product. Does that make sense?