2
The "2".
4
The last digit, 2.
7
It has no precision, since there is no following number.
In this case with 234.896 the last digit, '6' determines the precision since in is the last non-zero digit.
The precision is determined by the POSITION of the number 6 - NOT its value.
2
The "2".
4
3
The last digit, 2.
There a four significant figures in the number 16.82, the last '2' determines the best precision available.
7
7
8