Answer :

tenth: 243.9
hundredth:243.88

When you round you look to the place that is after it and if it is 5 or greater you round up (make the digit your round one bigger) and it is 4 or less you keep it the same (the digit your rounding doesn't change the same) 
43.586
tenth = 43.6
hundred= 43.69
one= 44

243.875
tenth= 243.9
hundred= 243.88
one= 244