Significant figures


What are significant figures?


Zeros to the left or right of the decimal place are not significant unless they are in between integers greater than zero.


Example 1:



Example 2:


Rounding to significant figures

Look at the last digit in the number if it is 5 or above the number to the left of it will increase by 1.

Example:
1463748

The 8 is greater than 5 so the number the left increases by 1 to become 5. As a result, you now have
146375

The 5 is equal to 5, so the number to the left increases by 1 to become 6.  As a result, you now have
14638

If you were to round 4934 to 1 significant figure, you would get 5000.  Confused?  This is because when using significant figures you need to keep the place values.  5000 has been rounded to 1 significant figure and is written like this:

5000 (1 s.f.) This indicates to the reader it has been rounded.

If you were to round 0.00034 to 1 significant figure it would look like this
0.0003 (1 s.f.) Again you must keep the place values.

If you were to round 23.0045 to 1 significant figure it would look like this
20 (1 s.f.).  This time only the zero before is kept, so you can see it is 20 and not 2.  

The best thing to do with any Maths is to keep practicing.  Write out some figures and then round them to 3 s.f. You can check your answers be using one of the online calculators. 

Until next time, peace.

Comments

Popular posts