Significant Figures

Significant Figures

By Aguado Angelica

Rule #1

ALL non-zero digits DO count!

​498

​

​

​3 sig figs!

​2 sig figs!

​1 sig fig!

​79

​2

Rule #2

Zeros to the right of decimal and a significant digit DO count.

​498.00

​

​

​4 sig figs!

​5 sig figs!

​3 sig figs!

​ 79.0

​2.000

Rule #3

Zeroes between significant figures DO count

​409

​

​

​5 sig figs!

​3 sig figs!

​4 sig figs!

​7006

​20004

Rule #4

Zeroes at the end of a whole number DO NOT count.

​400

​

​

​1 sig fig!

​1 sig fig!

​2 sig figs!

​7500

​20

Rule #5

Zeroes in front of a number as placeholders DO NOT count.

0.004

​

​

​2 sig figs!

​1 sig fig!

​4 sig figs!

​0.07500

​0.20

Multiple Select

How many significant figures are in 0.002010

• 7

• 2

• 4

• 3

Fill in the Blank

a) 2730.78 m

Fill in the Blank

0.0076 mL

Fill in the Blank

3400 kg

Fill in the Blank

3400.0 m2

Significant figures in addition and subtraction

For addition and subtraction use the following rules: Count the number of significant figures in the decimal portion ONLY of each number in the problemAdd or subtract in the normal fashionYour final answer may have no more significant figures to the right of the decimal than the LEAST number of significant figures in any number in the problem.

Fill in the Blank

15.773 + 2.8 = ?

Fill in the Blank

144 + 12.221 = ?

Fill in the Blank

20.057 - 2.1 = ?

Multiple Select

234.22 - 34.1 =

• 200.12

• 200.1

• 200

• 2

Significant Figures in Multiplication and Division

For multiplication and division use the following rule: 

The LEAST number of significant figures in any number of the problem determines the number of significant figures in the answer. (You are now looking at the entire number, not just the decimal portion)

*This means you have to be able to recognize significant figures in order to use this rule*      

Example: 5.26 has 3 significant figures; 6.1 has 2 significant figures

Multiple Choice

Which answer is rounded to the correct place for the equation below?

487.0 / .0024 = 121750.0

• 121750.0

• 121800

• 122000

• 120000

Multiple Choice

Select the answer reported to the correct number of significant figures.

85 X 973

• 82705

• 82710

• 82700

• 83000

Multiple Choice

Select the answer reported to the correct number of significant figures. $$930\div412$$  

• 2.25728

• 2.26

• 2.25

• 2.3

Multiple Choice

3.11 x 2.1 =

• 6.531

• 6.53

• 6.5

• 7

• 6