To find the greatest decimal, compare place values left to right: ones, tenths, hundredths.

Numbers	=	6.01, 6.10, 6.00, 6.11
All have ones digit 6. Compare tenths: 0, 1, 0, 1. 1 is greater. Between 6.10 and 6.11, compare hundredths: 0 < 1. So 6.11 is the greatest.
Greatest	=	6.11