Master Significant Figures
Complete guide to significant figures with free interactive practice tools. Learn counting and rounding with step-by-step explanations
What are Significant Figures?
Understanding precision and accuracy in measurements
Significant figures (also called significant digits) are the digits in a number that carry meaning and contribute to its precision. They indicate how precise a measurement or calculation is. Understanding significant figures is essential in science, engineering, and mathematics to ensure accurate reporting of results.
Counting Significant Figures
Learn to identify and count all significant digits in a number, including those in scientific notation and decimal numbers.
Practice Counting →Rounding to Significant Figures
Master the art of rounding numbers to a specific number of significant figures while maintaining precision.
Practice Rounding →Scientific Applications
Essential for accurate scientific measurements, laboratory work, and reporting experimental results with proper precision.
Rules of Significant Figures
Master the fundamental rules for counting significant figures
Rule 1: Non-zero digits are always significant
All non-zero digits (1-9) are significant. For example, 123 has 3 significant figures.
Examples: 45 (2 SF), 789 (3 SF), 1234 (4 SF)
Rule 2: Zeros between non-zero digits are significant
Zeros between non-zero digits are always significant. For example, 101 has 3 significant figures.
Examples: 101 (3 SF), 2005 (4 SF), 1.009 (4 SF)
Rule 3: Leading zeros are not significant
Zeros that appear before the first non-zero digit are not significant. They only indicate the position of the decimal point.
Examples: 0.05 (1 SF), 0.0034 (2 SF), 0.00012 (2 SF)
Rule 4: Trailing zeros in decimals are significant
Zeros after the decimal point and after non-zero digits are significant. For example, 5.00 has 3 significant figures.
Examples: 5.00 (3 SF), 12.50 (4 SF), 0.120 (3 SF)
Rule 5: Trailing zeros in whole numbers may or may not be significant
Without a decimal point, trailing zeros in whole numbers are ambiguous. Use scientific notation for clarity.
Examples: 1200 (ambiguous), 1.20 × 10³ (3 SF), 1.2 × 10³ (2 SF)
Rule 6: Scientific notation shows significant figures clearly
All digits in the coefficient of scientific notation are significant. The exponent indicates magnitude only.
Examples: 3.45 × 10² (3 SF), 1.2 × 10⁻³ (2 SF)
Significant Figures Examples
See how to count significant figures in different scenarios
Counting Examples
Why Significant Figures Matter
Significant figures indicate the precision of measurements and calculations. Using the correct number of significant figures ensures that results are reported with appropriate accuracy.
Scientific Applications
Essential for laboratory work, scientific reporting, and ensuring calculations maintain appropriate precision throughout experiments and data analysis.
Significant Figures vs Decimal Places
Understanding when to use each precision concept
Key Difference
Significant figures count all meaningful digits, while decimal places count only digits after the decimal point. For example, 123.45 has 5 significant figures and 2 decimal places.
When to Use Significant Figures
Use significant figures for scientific measurements, laboratory data, and when precision of the entire number matters.
When to Use Decimal Places
Use decimal places for currency, percentages, and when you need a specific level of precision after the decimal point.
Master Both Concepts
Our platform offers comprehensive practice for both significant figures and decimal places, helping you master precision concepts for any application.
Start Practicing Significant Figures
Choose your practice tool and begin mastering significant figures
Count Significant Figures
Learn to identify and count significant figures in any number with instant feedback.
Start Counting PracticeRound to Significant Figures
Master rounding numbers to a specific number of significant figures with step-by-step explanations.
Start Rounding PracticeDecimal Places Practice
Also practice decimal places to master both precision concepts in mathematics.
Learn Decimal Places