4. The zeroes to the left are not significant, the zero to the right, is.
2 significant figures.
There are 3 significant figures in this number.
There are 6 significant figures in this length.
3 significant figures.
It has 2 significant figures. However, the fact that it is given as 2300 mm and not as 230 cm suggests that it is, in fact significant to 4 figures.
2 of them.
4
111.009 mm rounded off to four significant figures is 111.0
3 of them.
The measurement 1456 mm has four significant figures. All non-zero digits are considered significant, and since there are no leading zeros or decimal points that would affect the count, each digit (1, 4, 5, and 6) is significant.
The least number of significant figures in any number of the problem determines the number of significant figures in the answer.
110.1mm