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 places behind decimal
The number with the smallest amount of places behind the decimal determines how many places behind the decimal should be in your answer.
Ex.
cm – 23.7 cm =
385.6 cm
3.85 g g g =
229.5 g