Root "cur" is originated from Latin word "cūrāre", means care, cure or manage.
"grad" and "gress" are originated from Latin verb gradus/gressus, meaning to walk or to advance.
cred originates from Latin word crēdere, means "to believe."
Prefix "sym" or "syn" originates from Greek, meaning with or together with. The prefix can also be "sy" or "syl" in spelling.
"ex" means out/outside, "extra" means outside/except/without, both originate from Latin.