There really doesn't need to be a separate explanation for each number because 1 explanation would explain everyone of them.
All of these numbers are rational because a rational number is, or can be, turned into a fraction.
-2 = -2/1
3 = 3/1
819 = 819/1
1,476 = 1,476/1
-6.01 = -6 1/100 = -601/100
