Significant figures (also known as the significant digits, precision or resolution) of a number in positional notation are digits in the number that are reliable and absolutely necessary to indicate the quantity of something.

1. SIGNIFICANT FIGURES

2. DEFINITION
THE TOTAL NUMBER OF DIGITS IN THE NUMBER IS CALLED THE NUMBER OF SIGNIFICANT FIGURE.

3. IMPORTANT POINT:
IT IS EQUAL TO THE NUMBER OF DIGITS
WRITTEN INCLUDING THE LAST ONE, EVEN
THOUGH ITS VALUE IS UNCERTAIN.

4. TABLE CONTENTS
DIGIT SIFGNIFICANT NUMBER RULE
101 3 (i)
0.101 3 (ii)
0.0101 3 (iii)
101.0 4 (iv)
101.00 5 (ii)

5. THE FOLLOWING RULES SHOULD BE FOLLOWED
IN COUNTING THE SIGNIFICANT FIGURES.
RULES

6. RULE NO:1
1. ALL DIGITS ARE SIGNIFICANT EXCEPT
ZERO AT THE BEGINNING OF THE
NUMBER.

7. 2. THE ZEROS TO THE RIGHT OF THE
DECIMAL POINT ARE SIGIFICANTS.
RULE NO:2

8. Significant figures in numerical calculations
• RULE 1:
• SIGNICANT FIGURE RULE IN MULTIPLICATION/DIVISION
14.79×12.11×5.05
904.48985
=
904.48985
=
9.04× 104
ROUND OFF

9. Significant figures in numerical calculations
• RULE 2:SIGNICANT FIGURE RULE IN aDDITION/SUBTRACTION
22.2+2.22+0.222 = 24.642
24.6
=