I've recently started university and every time I'm facing this problem and I would like by you guys really to overcome on that problem.

what's Number?! I mean since we do manipulations on numbers like 5+1 =6 and other manipulations on numbers ..may anyone explain or analog me the definition of number at all?!

for example I can't do "label 1" + 1 = ?! (not known) and because "label 1" isn't a number it's label, but I missunderstanding the concept/term of definition a number ..so please may anyone illustrate that point what's number?!!

thanks in advance for you all