Significant Figures

What is an exact number?

• A number that is uncertain

• A number that is measured

• A number that is certain

• A number that changes frequently

Which of the following is an example of an exact number?

• The length of a piece of string

• The weight of a bag of apples

• 12 eggs in one dozen

• The temperature of a room

What is an inexact number?

• A number that is always whole

• A number that is certain

• A number that is measured

• A number that is infinite

Why are numbers obtained from measurement never exact?

• Because the measuring tool is always precise

• Because there is no need for exact numbers in science

• Because there is always a degree of "uncertainty" due to the measuring tool and the individual doing the measuring

• Because measurements are always estimated

How many significant figures are there in the number 4.09?

• 2

• 3

• 4

• 5

How many significant figures does the number 61.02 contain?

• 2

• 3

• 4

• 5

If a number ends with zeros that are after the decimal point, such as 0.500, how many significant figures does it have?

• 2

• 3

• 4

• 5

How many significant figures are in the number 3.00?

• 1

• 2

• 3

• 4

How many significant figures does the number 0.0025 have?

• 4

• 2

• 3

• 5

How many significant figures are there in the number 1000 when it does not have a decimal point?

• 4

• 1

• 3

• 2