Significant Figures

Question

Indicate how many significant figures would be reported in the sum, difference, product, or quotient for the following:

 

33. 4506.23 + 9000 =

 

35.  8.00 x 10^2 + 76.345002 =

 

Thank you!

Answer 1

For Q #33:

 

4506.23 + 9000 =?

FIRST, notice that 9000 (as it is typed here with no decimal point at the end of the "9000") would have a "calculator" display of 13,506.23 BUT that is NOT what you should write down!

 

Since this is an addition problem, you respect the "least number of decimal places" with regard to sig. figs. on EACH number in the addition problem setup.  When reporting your answer, you must report it with the least number of decimal places.  Also note that if "9,000" were written as "9,000.", then you would report your answer as 13,506.

 

For Q #35:

 

8.00 x 10^2 + 76.345002 = ?

Notice first that this is ALSO addition, thus you are to report your answer in the "least number of decimal places " yet again! which is TWO due to the "8.00", so the "calculator" display for the answer should be 876.345002 which should be rounded off to 2 decimal places giving 876.35

 

Summary:  When adding or subtracting numbers, you are limited to the LEAST NUMBER OF DECIMAL PLACES when reporting your answers.  When multiplying or dividing numbers you are limited to reporting your answers in the LEAST NUMBER of sig. figs.

 

Hope this helps!