Significant Digits

Definition of Significant Digits

• Significant digits are digits that express the accuracy for a measurement.

                        

Examples of Significant Digits 

• There are 4 significant digits in the number 52,790.

5, 2, 7, 9 are the significant digits

• There is only one significant digit in the number 0.0001 – only 1 is a significant digit.

                                               

More about Significant Digits

• The most significant digit in a number is the first nonzero digit in the number from left.

For example, in the number 439.205, 4 is the most significant digit though 9 is the largest digit, because 4 represents 4 hundreds whereas 9 represent 9 ones.

                              

Solved Example on Significant Digits

Find the number of significant digits in the measurement 4.07 cm.

Choices:

A. 2

B. 1

C. 4

D. 3

Correct Answer: D

Solution:

Step 1: The unit of measure used in the measurement is 0.01 cm. 407 such units give 4.07 cm.

Step 2: So the significant digits in the measurement are 4, 0, and 7 and thus there are 3 significant digits in the given measurement.

                        

          Related Terms for Significant Digits

• Digit
• Accuracy
• Measurement

                            

Additional Links for Significant Digits

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