Are all mathematicians human calculators? I asked my dad why he did not major in math he said "because he is not good at math".
I think I like math, and I think I'm ok at it, but I'm not gifted or anything like that, I just like math. I think I'd like to major in math, but I see all these documentaries about great mathematicians and they can all multiply and divide numbers off the top of their heads and I certainly cannot. I realize that we have calculators, but somehow I don't think I should go into math. 


  As a forum/site of math people, what do you think? 


Sorry if this is kind of a random question with no definite answer and probably out of place. My tags are probably wrong too, sorry.

EDIT: Mostly, i think I'm worried that I don't have a high enough IQ to ever contribute anything to the field of mathematics. I think I'll only study the work of others and never have my own work. It seems like people who are successful in mathematics are people who are talented by nature, like they have a really high IQ (yes, IQ is just a number, but you know what I mean) and math comes easily to them. For those people, it seems like math is effortless, but I wouldn't know.
Replace the captions in the below comic with "math fan" and "mathematician" and it will convey the spirit of the truth (link to original) :
The number of famous mathematicians in history who were also great mental calculators are few and far between.  Euler, who became blind in his latter years, is said to have been able to perform calculations in his head.  One story is that Euler passed away while he was mentally calculating the orbit of the moon.  Emilie du Chatelet is also another famous example.  It has been determined from his extant notes that Newton was not a mental calculator, though he did enjoy working out numerical calculations to something like 50 decimal places.  Gauss has also been named as a calculating prodigy.  Doron Zeilberger, though, has recently brought to light that Gauss' famous boyhood deduction of summing consecutive integers up to 100 was actually determined with inductive examples (as shown in his Tagebuch, i.e. diary) and not by other more direct means (as had previously been promulgated).  The reader should take caution that we are talking about famous people in history with many admirers and followers who very likely would not fall short of exaggerating their accomplishments.  In the 20th century, we have Alexander Aitken and John von Neumann.  There are several anecdotes about von Neumann, who was able to solve the two trains and a fly problem the long way by summing geometric series in his head, according to Eugene Wigner.   Feynman was perhaps not a calculating prodigy in the same league as a real mental calculator, but he did explain some of his tricks and techniques with regards to mental calculations.