Three. All non-zero digits are significant, all zeroes between other digits, and all digits to the right of the decimal. The reason for this is that if this is rounded off, it apparently is rounded off to the nearest tenth, otherwise the tenth place would not be shown. if it were rounded off to the unit, it would read 39, not 39.0 ■
111.0
0.999 All leading zeros are non-significant.
9,990 to 3 s.f., or 9,990 (3 s.f.) or 9,990
1,040 to 3 s.f., or 1,040 (3 s.f.) or 1,040.
111.009mm rounded to four significant digits is 111.0mm
111.009 rounded to four significant digits is 111.0
1042L rounded off to two significant digits is 1000L. The digit "1" in the hundreds place is the most significant digit, so the number is rounded down to 1000L.
14.587020 rounded to four significant digits is 14.59
31500
16.3
Three. All non-zero digits are significant, all zeroes between other digits, and all digits to the right of the decimal. The reason for this is that if this is rounded off, it apparently is rounded off to the nearest tenth, otherwise the tenth place would not be shown. if it were rounded off to the unit, it would read 39, not 39.0 ■
111.0
111.0
1.0e3L
6.71 is 6.7050 is rounded to three significant figures.
0.999 All leading zeros are non-significant.