Using a scientific calculator on math tests
With exams fast approaching, this is a short article with reminders and tips for anyone about to take a math test who needs to use a scientific calculator.
– set the calculator to the correct mode
– Can’t find calculator manual!
– remember to change calculator modes
– rounding and inaccurate answers
Why use a scientific calculator?
All scientific calculators use the same order to perform mathematical operations. This order is not necessarily the same as simply reading a calculation from left to right. The rules for performing mathematical calculations specify the priority, and therefore the order, in which a calculation must be performed: scientific calculators follow the same order. This order is sometimes abbreviated with terms such as BODMAS and BIDMAS to help students remember the order in which calculations are performed.
1st supports (All calculations inside parentheses are done first)
2nd. Operations (for example, squaring, cube, square root, sin, cos, tan )
3rd. Division and Multiplication
4th. addition and subtraction
Being aware of this order is necessary to be able to use a scientific calculator correctly. This order should always be used in all mathematical calculations, whether a calculator is used or not.
Checking scientific calculator
There are two types of scientific calculator, the newer type is algebraic scientific calculators. Algebraic scientific calculators allow users to write calculations in the order they were written. Older scientific calculators require users to press the math operation key after the number has been entered.
For example, to find the square root of nine (with an answer of three), press: [button]
Algebraic Scientific Calculator: [SQUARE ROOT] [9] [=]
Non-Algebraic Scientific Calculator: [9] [SQUARE ROOT] [=]
Both types of scientific calculator are fine for tests, but make sure you know how to use your own type.
If you are not sure whether you have a scientific calculator or not, type:
[4] [+] [3] [x] [2] [=]
If you get an answer of 14, then you have an unscientific calculator from left to right.
If you get an answer of 10, then you have a scientific calculator, since it solved the multiplication part first.
lost calculator manuals
Calculator manuals tend to get lost very easily or can never be found when an exam is coming up. A frequently asked question is what can you do if you have lost the manual for your calculator? If it’s a relatively new model, you can download a copy from the manufacturer’s website. If it’s an old Sharp or Casio calculator manual, you can still find them on the internet. Even with search engines, finding these manuals can take some time. The following link has information on old and new calculator manuals for Casio, Sharp, Hewlett-Packard, and Texas Instruments: here.
calculator mode
Now that you have the manual for your calculator, you can set it up with the correct settings. The standard settings are usually:
COMPUTATIONAL:
(use MODE button – choose normal no stat) NO: SD or REG
DEGREES:
(use MODE or DRG button) NO: RAD OR GRAD
NORMAL:
(use MODE or SETUP and arrow keys) NOT: FIX, SCI, ENG
Many calculators have a reset button on the back that can be pressed with a pen or paper clip if you want the original factory settings.
The most common mistake is to leave the calculator in a previous mode and FORGET TO CHANGE IT AGAIN! (We all have, just try to avoid doing it on the test!)
common errors calculator
(a) Pressing the DRG button by mistake and not asking trigonometry questions in DEGREES mode. (If you’re doing more advanced work, then you forget to change the DEGREES mode!).
(b) Borrowing an unfamiliar calculator or buying a new calculator too close to the exam and not being familiar with the keys and how to change modes.
(c) Forgetting to record and check the work. Any test with a calculator should have a warning! It is essential to write down the calculations you are doing so that you can earn method grades. You should also try and double check all the calculations in case of pressing a wrong button.
(d) Rounding before the end of a calculation. Store calculations in memory and use all decimal places during calculations. If you use a rounded value too early, you will lose precision.
(e) Forgetting to use square brackets in division calculations (for example, when dividing by ALL of the bottom part of a fraction).
Many calculators are now very powerful and have amazing computational power. Some of the programmable calculators are mini computers. Although they will all calculate with 100% accuracy every time, unfortunately, they are only as good and accurate as their operator!
It is often the case that candidates do better without a calculator, as it is very easy to make simple mistakes when using one. If you can do it, it certainly helps to have an idea of the approximate size of the answer, so you can see if an answer is sensible or not. It’s also a good idea to repeat all the calculations in case you’ve made a mistake while pressing a key.