Significant Figures

All digits including zeros are significant

7.0 × 10^-9 (2 sig fig)

6.02 × 10²³ (3 sig fig)

All nonzero digits are significant

3.4 (2 sig fig)

25.85 (4 sig fig)

zeros placed between nonzeros are significant

5.04 (3)

8.0045 (5)

zeros placed at the end of a number when a decimal point is present is significant

4.0 (2)

40. (2)

zeros placed at the end of a number when a decimal point is not present are NOT significant

40 (1)

6510 (3)

zeros placed at the beginning of a number are NOT significant

0.1 (1)

0.0006 (1)