Just take away the numbers from the right one by one until you have 3 decimal numbers left.
29
87.656 87.66
It is: 2986.342 to three decimal numbers
33.487 is already rounded to three decimal places. if it were 33.4829, which is four decimal places, you would round it to the nearest three DECIMAL places, which would be 33.487. So, the answer to your question is; 33.487 is already rounded to three decimal places.
No
6.857142 rounded to three decimal places is 6.857.
585.9607377 rounded to three decimal places is 585.961.
Rounded to three decimal places, this is equal to 1.397.
146.875 rounded to three decimal places is 147.
Leave it as it is because it is already in three decimal places
85 rounded to three decimal places is 85.000
Just as it is. 0.581 is already rounded to three decimal places.
Rounded to three decimal places, this is approximately equal to 6.966.