What is f(×)=[×]-3 evaluated for ×=-2.8

Question

I don't get what I have to do after I plug in the -2.8 .

Answer 1

Assuming that [ ] is the greatest integer function:

 

[-2.8] = -3

f(2.8) = [2.8] - 3

f(2.8) = -3 - 3

f(2.8) = -6