What is that word?

Waht is the word to describe a person who makes carelessly tiny mistakes all the time?

For example:

I have a p.t job, which is to correct kids' homework.

And sometimes I check them wrong just because I accidently missed out a word or something .

But I do know the answer.

And I forget tiny things often, or something like that.

How would you put that in word??

Please give me "noun, adj., and adv"

THANKS!!