Regents Prep Math A Regents Prep Home Page

(Information presented on this page is an amended excerpt from the State Education Department document "Instructional Recommendations for High School Mathematics Instruction."

Use your calculator's full display.

     Unless otherwise specified, the full power/display of the calculator should be used.  Remember that when you round a number, you obtain an approximate answer.  The more decimal places you can maintain, the more accurate your answer will be.  Don't be afraid to let your calculator work with its full display of decimal places.

Don't round too soon!

     You should NOT be rounding as you are working on a problem.  Rounding should be done only when the final answer is reached.   Try to keep your full calculator display until you are ready to round the final answer.  See the examples at the bottom of this page.

Common repeating decimals should be changed to fractions.

     Be sure that you know how to use the fraction command on your calculator to convert to a fraction instead of rounding common repeating decimals.
                                          For example:  .3333333333333 =

Remember that is NOT 3.14

     You must remember that  is an irrational number which is not equal to the common rational approximations, 3.14 and . 
*** Unless otherwise specified, the key on a calculator should be used in computations.
 


Look carefully at these examples:

Question 1:
Find the difference between the area
of two circles whose radii are 10 inches
and 5 inches.   Express the answer in decimal form to the nearest hundredth.		 Answer:
The areas of the circles are and .
The difference of should be found first and then the value 235.619449 square inches should be calculated using the key on the calculator.  The value of 235.619449 can then be rounded to 235.62.
BEWARE!!  You should NOT approximate the two areas as 79 and 314 before finding the
                      difference between them.


 
Question 2:
Find the ratio of the areas of two circles whose areas are and .
 		 Answer:
The correct ratio is .
BEWARE!!  You should not calculate and round to 78.5 or 79.  Likewise,should not be rounded to 314.16 or 314.  The answer is not 79/314.


Math A