Is 6.52 grater then 6.520

No 6.52 is equal to 6.520.
The reason for this is because even if you add more ceros to the othe side of 6.52 it would not matter unless there is another number other than 0, Like 6.52000000000000001 is bigger than 6.52 ans smaller tahn 6.5200000000000000000000

No its equal it doesnt change if you put a 0 at the end

8doors on the second floor