**Using a Scientific Calculator In Mathematics Exams**

With exams approaching this is a short article with reminders
and advice for anyone about to take a mathematics exam and who
will need to use a scientific calculator.The most common
calculator problems are:
- setting up the calculator in the right mode - not being able
to find the calculator manual ! - remembering to change
calculator modes - rounding and inaccurate answers
**Why Use a Scientific Calculator ?**
Scientific calculators all use the same order for carrying out
mathematical operations. This order is not necessarily the same
as just reading a calculation from left to right. The rules for
carrying out mathematical calculations specify the priority and
so the order in which a calculation should be done - scientific
calculators follow the same order. This order is sometimes
abbreviated by terms such as BODMAS and BIDMAS to help students
remember the order of doing calculations.
**1st. Brackets** (all calculations within bracket are done
first) **2nd. Operations** (eg squaring, cubing, square
rooting, sin, cos, tan ) **3rd. Division and Multiplication**
**4th. Addition and Subtraction**
Being aware of this order is necessary in order to use a
scientific calculator properly. This order should always be used
in all mathematical calculations whether using a calculator or
not.
**Scientific Calculator Check**
There are two types of scientific calculator, the most recent
type being algebraic scientific calculators. Algebraic
scientific calculators allow users to type in calculations in
the order in which they have been written down. Older scientific
calculators need users to press the mathematical operation key
after they have entered the number.
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 these types of scientific calculator are fine for exams,
but make sure you know how to use your type.
If you are not sure whether you have a scientific calculator
are not, type in: [4] [+] [3] [x] [2] [=]
If you get an answer of 14, then you have a left to right
non-scientific calculator. If you get an answer of 10, then you
have a scientific calculator as it has worked out the
multiplication part first.
**Lost Calculator Manuals**
Calculator manuals tend to get lost very easily or you can never
find them as an exam is approaching. A frequent request is what
can you do if you have lost your calculator's manual? If it is a
relatively new model then you can download a copy from the
manufacturer's web site. If it is an old Sharp or old Casio
calculator manual then you can still find these on the internet.
Even with search engines, finding these manuals can take some
time - the following link has information about new and old
calculator manuals for Casio, Sharp, Hewlett-Packard and Texas
Instruments: here.
**Calculator Mode**
Now that you have your calculator manual you can set your
calculator to the correct settings. The standard settings are
usually:
**COMPUTATIONAL:** (use MODE button - choose normal not
stat) NOT: SD or REG **DEGREES: ** (use MODE or DRG button)
NOT: 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 in using a pen or paper clip if you want the original
factory settings.
The most common mistake is to leave your calculator in a
previous mode and FORGETTING TO CHANGE IT BACK AGAIN ! (We've
all done it, just try to avoid doing it in the exam !)
**Common Calculator Mistakes**
(a) Pressing the DRG button by mistake and not doing
trigonometry questions in DEGREES mode. (If you are doing more
advanced work then forgetting to change out of DEGREES mode !).
(b) Borrowing an unfamiliar calculator or getting a new
calculator too close to the exam and not being familiar with the
keys and how to change modes. (c) Forgetting to write down and
check work. Any exam with a calculator should have a warning on
it! It is essential to write down the calculations that you're
doing so that you can get method marks. You should also try and
double check all calculations in case of pressing a wrong
button. (d) Rounding only at the end of a calculation. Store
calculations in the memory and use all the decimal places during
calculations. If you use a rounded value too soon then you will
lose accuracy. (e) Forgetting to use brackets on division
calculations (e.g. when dividing by ALL 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 100% accurately
every time, unfortunately they are only as good and as accurate
as their operator!
It is often the case that candidates perform better without a
calculator as it is very easy to make simple mistakes when using
one. If you can do so, it certainly helps to have an idea of the
rough size of the answer, so that you can see if an answer is
sensible or not. It is also a good idea to repeat all key
presses just in case you have made a mistake.