find command in Linux

Question

I try to find files changed in some interval of time in directory hierarchy beginning from current directory, I try:
find . -mmin 60
find . -mtime 60
But I didn't get result. I get results only if I write in -mmin/mtime parameter exactly (!) time that before that file was changed, so for example:
find . -mmin 2
Get 2 results
find . -mmin 3
Get 3 other (!) result
find . -mmin 60
Not get result

When I get 60 minutes interval, I need see files even changed before 10 minutes.
I read man find and not found what I need.

Thank you very much for ahead.

Answer 1

From the find(1) man page, EXPRESSIONS section, TESTS subsection:

   Numeric arguments can be specified as

   +n     for greater than n,

   -n     for less than n,

   n      for exactly n.