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

Numbers	=	8.99, 9.80, 9.98, 8.00
Compare ones: 8, 9, 9, 8. 8 is smaller than 9. Between 8.99 and 8.00, compare tenths: 0 < 9. So 8 is the smallest.
Smallest	=	8