What is the greatest integer of 5.8

http://www.mathnstuff.com/math/spoken/he…

this says the greatest integer is the first integer that is less than or equal to 5.8

5.8 is < than 6.0 so 6.0 is NOT the greatest integer

5.0 < 5.8 so 5 is the GREATEST INTEGER

5.8=>5

(5+12)/2 = 17/2 = 8.5 I think