Significant Figures

Significant Figures

by Rayon Fagon

​Significant Figures

​The number of meaningful digits in a number that convey its meaning according to its accuracy.

​

​

​

​

s.f. is short for significant figure(s)

​Rules

1. All non-zero digits are significant (12345)

2. All zeros between non-zero digits are significant​. (109.0043 s.f. = 7)

3. ​Zeros to the right of a decimal point and left of a non-zero digit are NOT significant. (0.0045 s.f. = 2)

4. ​Zeros to the right of the last non-zero digit after a decimal point are significant. (0.003260 s.f. =4)

​Rounding to Given Significant Figures

​To round a number to a given number of significant figures:

• ​Identify the digit in the required significant position.

• ​Note the digit to the immediate right of that position.

• ​If the value of that digit is 5 or greater, round up by adding one to the digit in the required position.

• ​If the value of the digit is less than 5, round down using zeros as place holders.

Multiple Choice

State the number of significant figures for the number 2 400

• 1

• 2

• 3

• 4

Multiple Choice

State the number of significant figures for the number 560 001

• 3

• 4

• 5

• 6

Multiple Choice

State the number of significant figures for the number 0.0708

• 2

• 3

• 4

• 5

Multiple Choice

State the number of significant figures for the number 0.0008

• 1

• 2

• 3

• 4

Multiple Choice

State the number of significant figures for the number 4.000

• 1

• 2

• 3

• 4

Multiple Choice

Round off 86 472 to 3 significant figures.

• 864

• 865

• 86 400

• 86 500

Multiple Choice

Round off 0.002496 to 2 significant figures.

• 0.0024

• 0.0025

• 0.002400

• 0.002500

Multiple Choice

Round off 35.089 to 1 significant figures.

• 4

• 30

• 40

• 40.000

Multiple Choice

Round off 1.03028 to 4 significant figures.

• 1.030

• 1.0302

• 1.03000

• 1.03020

Multiple Choice

Round off 96.011 to 3 significant figures.

• 90

• 96

• 96.0

• 96.000

Multiple Choice

45092 in standard form correct to 3 significant figures

• $$4.5092\times10^4$$  

• $$4.50\times10^4$$  

• $$4.51\times10^4$$  

• $$4.509\times10^4$$