Are all mathematicians human calculators? [closed]

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) :

We invented computers to avoid precisely that...