Metal Gear Solid 4 has a review score of 99

[a.l.e.x00]

You're wrong. 18/20 = 90/100 because 18 times 5 = 90 and 20 times 5 = 100. therefore, because 90/100 = 18/20 its the same thing. its called the lowest common denominator, I think. Right? Same with the 4/5 one.