In aerobic respiration, total number of ATP molecules formed from 1 glucose molecule is

The net gain from complete oxidation of a glucose molecule in aerobic respiration is 36 ATP molecules. 10 molecules of $\mathrm{NADH}_2$ ( 2 from Glycolysis +8 from Krebs' cycle) yield $=10 \times 3=30 \mathrm{ATP}, 2$ molecules of $\mathrm{FADH}_2$ yield $=2 \times 2=4$ ATP and glycolysis also yields 2 ATP. Therefore, total release of ATP per hexose will be $=30+4+2=36$ ATP.