Can you do math in your head well?

When you have to do something related to math (not just in a math related class, any kind of adding, etc. throughout life) are you able to do most calculations in your head, or do you actually have to write it out/use a calculator?

Personally I'm pretty good with doing it in my head, usually I don't just carry around a calculator when I have to add numbers or something. With very large numbers, though, I cannot for the most part.

I've usually been fine at doing basic like addition and multiplication, but I've been doing more long division by hand to try and get myself to be able to do it in my head without need of writing it down or using a calculator.

I can do the basic math in my head but, not the harder stuff like find the value of X, A and Z.

^ Oh yeah, neither can I. I was mostly talking about simple addition, multiplication, and subtraction really.

My sweetie can better then I do... Though for some odd reason I'm better with math when it comes to money though... ^^;

I would hope so....but, in reality, I get them wrong more often than I would like to admit  .