1. Significant Digits

2. Rules for determining how many SD’s are in a number
If it is not zero, it IS significant!
Ex: all digits are significant in
45.2 cm
91,722 mL
1.2 kg
Zeros in a “zero sandwich ARE significant!
Ex: all significant in
405 Mm
23,009 L
100,003 ng

3. Rules for determining how many SD’s are in a number
If no decimal is showing, zeros to the right ARE NOT significant!
Zeros are not significant in:
3400 dg
300 L
12,450 pm
In small decimal numbers, zeros to the left ARE NOT significant! ng
0.231 m kL

4. How many SD’s in:
506 L
11.09 mg
5600 km dL
45.00 s mm

5. Multiplication/Division using SD’s
Least total SD’s!
The number with the smallest amount of significant digits determines how many SD’s are in your answer
Examples:
5.670 m X 3.4 m =
19 m2
45.60 m / 3.70 s =
12.3 m/s

6. Addition and Subtraction Using SD’s
Least significant placeholder
The number with the least significant placeholder determines the least significant placeholder in your answer.
Ex.
cm – 23.7 cm =
385.6 cm
3.85 g g g =
229.5 g