This document discusses significant figures and the rules for determining the number of significant figures in measurements and calculations. It defines significant figures as the reliable figures in a measurement and provides examples of applying the rules to determine significant figures in numbers with decimals and commas. It also provides an example of rounding a number to a specified number of significant figures and notes that intermediate calculations should keep one more significant figure than the final answer.

3. Significant figures – the number of figures that are
known with some degree of reliability
Rules:
• All non-zero digits are significant
example:
1.235 gms has 4 sig figs
1.6 gms has 2 sig figs
3000 km has 1 sig fig
• Zeros between non-zero digits are significant
examples:
• 2005 km has 4 sig figs
• 1.02 has 3 sig figs

4. • Zeros to the left of the first non-zero digit are not
significant (they just indicate position of decimal
point)
Examples:
0.05 cm has only 1 sig fig
0.063 g has 2 sig figs
• Zeros placed after other digits but to the right of
the decimal point are significant
Examples:
0.200 ml has 3 sig figs

5. • For non-decimal numbers, zeros after the last
non-zero digit are significant
Example:
354,700 has 4 sig figs

6. Ex. To enclose the irrigated area used for
cultivation in a farm 2306.51 m of wire is needed.
Write this length correct to 1 sig fig.

7. The Museo del Prado exposition held in Tokyo in
July 2006 had 501,932 visitors. Write down this
number correct to 3 sig figs.

8. In a certain school it costs $0.00873 to print out one
page. Write this number correct to one sig fig.

9. Using your GDC
When doing multi-step calculations, keep at least
one more sig fig in intermediate results than
needed in your final answer.
Example: 2.513
2 + 0.3

10. “unless otherwise stated in the question, all
answers should be given correct to 3 sig figs”