To answer we must first understand when to round up and round down.
Where the determined digit < 5 -- we round down
Where the determined digit >= 5 -- we round up
Now, apply this principle to 243.875.
Tenth: Determine the number which comes after the tenth spot, this is 7, and it is >= 5 - so we round up.
> 243.9
Hundredth: Determine the number which comes after the hundredth spot, this is 5, and it is >= 5 - so we round up.
> 243.88.
Ten: Determine the number which comes after the tens place, this is 8, and it is >= 5 - so we round up.
> 244
I'm not sure why you would ever need to round the hundreds place - so to refrain from provided incorrect information I will not be answering that one.
