Algebra symbol Help please?

Question

I need to know what these symbols are called (so I can learn the material) and what they do in these math probs. thank you for your time.

____5!____ <---(Fraction)

(5-2)! 2!

and

(2.645●5.5)/5

I am unsure as to the ! and the ● in these probs. What do they do? etc. Plz explain, not just answers. thank you

the dot is not a multiplication dot, like *or x it is a large black dot

someone told me

for the first:

(5*4*3*2*1)/(3*2*1)*(2*1) ?

Answer 1

factorial...