The tenths place is the place right after the decimal point. When rounding, you look at the next place over (which would be the hundredths place in this case) and look at the number closely. If it is 5 or more than 5, the hundredths place disappears and becomes 16.8. When rounding to a whole number, you do practically the same thing but you look at the ones place (the place right before the decimal point) and look at the next place over (tenths place). Again, is it 5 or more? Yes, so you round up to 17 and get rid of the tenths place and everything after.