Rounding to nearest Thousandth means , to round of to 3 decimal places.
It means we have to round off the number such that there should be only 3 digits after decimal .
Because , the first place after decimal is called Tenth place
Second place after decimal is called Hundredth place and
Third place after decimal is called Thousandth place.
It means we have to round off to 3 decimal places and
to round off to 3 decimal places , we see the 4th place , if the digit at 4th place is 5 or greater than we increase the digit at 3rd place by 1 ,
Otherwise if the number at the 4th place is less than 5 , then we leave the 3rd decimal place digit as it is.
4.063581
Now here the digit at 4th decimal place is 5
it means we increase third decimal place digit 3 by 1 , So it becomes 4
So after rounding off we get
4.064
