Are the actuarial exams hard? I heard that they are difficult. Is this true? Are they like the qualifying exams in grad school? For example, is the probability exam and the financial math exam comparable to qualifying exams (e.g. needs months and months of study)?
 A: I have taken the US SOA exams up through M and taken a qualifying exam at a US graduate school.  They are very different kinds of exams and so are a different kind of hard.  The mathematics involved in an actuarial exam isn't particularly advanced, but there is a lot of terminology to learn and concepts that you wouldn't spend much time on in math degree.  You shouldn't consider them trivial.  
My understanding of the later exams is they get closer to quals in character.  They are several hour written exams and they serve a similar purpose (making sure you have the required knowledge of the discipline).  In particular, there are a set of exams in the US called the EA exams that require memorization and application of a large chunk of IRS regulations.  I'm glad I decided to go to grad school before having to take those.
The nice thing about actuarial exams (and I think this is relatively universal) is that once you get a job you will get paid study time and financial rewards for passing them.   
A: Personal experience: I took the first two of the SOA/ASA/CAS exams (which is, if you are in the United States, the same as what you called the Exam P-Probability and Exam FM-Financial Mathematics) when I was finishing high school and starting college. Compared to graduate school (in mathematics) qualifying exams, they are much, much easier. (Though I heard that the latter exams in the CAS or ASA requirement series get quite a bit harder.) 
The probability exam, modulo some terminology/jargon issue, is actually not beyond the grasp of high-school level pre-calculus. You just need to have some experience dealing with probability and statistics. I think it is more of a test on problem solving skills than anything else. 
The financial mathematics one has quite a bit more specialist knowledge involved. I remember having to spend several months studying for it just because there were many concepts which were new to me. At the time I managed to pass it by mentally associating the various words with the mathematical concepts/formulae they involved; in hindsight it was definitely the wrong way to study. Anyway, the study material from the SOA is actually quite comprehensive for the first two exams. If you spend a few months going through them you shouldn't have too much trouble.
A: I have passed some of the earlier actuarial exams in the U.S. system, so they are jointly administered by the Society of Actuaries (SOA) and the Casualty Actuarial Society (CAS).  I have passed two qualifying exams in graduate school.  The qualifying exams were much more difficult, especially the exam I took over analysis, which is largely on Lebesgue measure and more general measures.
Now that I have gone through most of graduate school, I am very certain that studying for the actuarial exams will be easy.  What I mean is that the difficulty of math I have seen in graduate school is so much greater than the actuarial exams, that I will be able to understand everything I read, and will be able to apply it as well.
BUT, it will still take a lot of study time.  It is often said you will need to study for 150-300 hours to pass an actuarial exam.  This might go down a bit after graduate school, but you still have to read through 10-15 chapters of a textbook and learn pretty much everything in it, all the definitions and formulas and theorems.  And, then, you will want to practice as many old exam problems as you can, because they are most likely more difficult than the problems from the textbook you learned the material from.
Let me put it this way.  If you were a good math student at a top 80 grad school, and you only studied for actuarial exams for a three or four months (no other job), you could probably pass 2 or 3 or 4 exams all at once.  But, I wouldn't do more than 2 or 3 because companies don't want to pay people a lot of money when they don't have any experience.
A: If you are referring to the actuarial exams in the United States, obviously different people have different reactions, but they are designed to be hard in the sense that they are designed so that students will study for months to pass them. The pass rate for the first exam (exam P) is about 40 percent, and the pass rate only slowly increases with the higher exams. Most actuaries fail exams along the way, and it's not uncommon for an actuary to have one exam in particular he/she gets stuck on and has to retake several times. And some give up altogether. 
