I just checked on Wikipedia and it is right the way that it is stated in the task. This is because if you add zeros after the decimal point, you imply that your number was "measured" with a higher precision.
Example: a normal ruler vs. a precision measuring devices
If you use the normal ruler you can only be certain your measured distance is 1.5cm
With a precision ruler you can be certain, that your measured distance is something like 1.500cm
Interestingly enough, technically, according to Wikipedia we have no way of knowing whether any zero to the right of the last non-zero digit is significant or not, regardless of the presence of decimals. So the exercise is still not quite right.
I just checked on Wikipedia and it is right the way that it is stated in the task. This is because if you add zeros after the decimal point, you imply that your number was "measured" with a higher precision.
Example: a normal ruler vs. a precision measuring devices
If you use the normal ruler you can only be certain your measured distance is 1.5cm
With a precision ruler you can be certain, that your measured distance is something like 1.500cm
Oh, so it's a measurement thing.
Interestingly enough, technically, according to Wikipedia we have no way of knowing whether any zero to the right of the last non-zero digit is significant or not, regardless of the presence of decimals. So the exercise is still not quite right.
I feel like the exercise is fine. It defines a definite rule for deciding on which trailing zeros are significant and which aren't.