Phone.jpgComputers and calculators are the tools of modern mathematicians.



A graphical calculator
    • Try not to use your calculator for simple calculations involving adding, subtracting, dividing and multiplying whole numbers.

e.g. 8 × 7 or 56 + 72.

  • Keep the instruction booklet that comes with the calculator. You will need it for the more complicated calculations and functions.
  • Estimate the answer to the calculation before you start. This is a good check in case you press the wrong keys.

There are many makes and types of calculators. 
The examples below use keys typical to most scientific calulators.


To enter negative integers into a calculator use the Y9_Spreadsheets_and_Calculators_02.gif . On some calculators this button Y9_Spreadsheets_and_Calculators_03.gif is used.

e.g. To calculate -3 + -7 press:

Y9_Spreadsheets_and_Calculators_02.gif Y9_Spreadsheets_and_Calculators_04.gif Y9_Spreadsheets_and_Calculators_05.gif Y9_Spreadsheets_and_Calculators_02.gif Y9_Spreadsheets_and_Calculators_06.gif Y9_Spreadsheets_and_Calculators_07.gif -10


Some calculators have a fraction button Y9_Spreadsheets_and_Calculators_08.gif .

e.g. To calculate 34 + 89 press:

Y9_Spreadsheets_and_Calculators_04.gif Y9_Spreadsheets_and_Calculators_08.gif Y9_Spreadsheets_and_Calculators_11.gif Y9_Spreadsheets_and_Calculators_05.gif Y9_Spreadsheets_and_Calculators_12.gif Y9_Spreadsheets_and_Calculators_08.gif Y9_Spreadsheets_and_Calculators_13.gif Y9_Spreadsheets_and_Calculators_07.gif 1 23 36 which means 12336

If your calculator does not have a fraction button press:

Y9_Spreadsheets_and_Calculators_04.gif Y9_Spreadsheets_and_Calculators_15.gif Y9_Spreadsheets_and_Calculators_11.gif Y9_Spreadsheets_and_Calculators_05.gif Y9_Spreadsheets_and_Calculators_12.gif Y9_Spreadsheets_and_Calculators_15.gif Y9_Spreadsheets_and_Calculators_13.gif Y9_Spreadsheets_and_Calculators_07.gif 1.638888889 which is equivalent to 12336


Calculators have special buttons for square roots Y9_Spreadsheets_and_Calculators_17.gif and cube roots Y9_Spreadsheets_and_Calculators_18.gif . To find any other roots use the button Y9_Spreadsheets_and_Calculators_19.gif

e.g To find the fourth root of 16,i.e. Y9_Spreadsheets_and_Calculators_20.gif press:

Y9_Spreadsheets_and_Calculators_11.gif Y9_Spreadsheets_and_Calculators_19.gif Y9_Spreadsheets_and_Calculators_21.gif Y9_Spreadsheets_and_Calculators_22.gif Y9_Spreadsheets_and_Calculators_07.gif   2

Standard form

To enter a number in standard form into a calculator:

Standard form
Enter 2.3 × 104 into calculator Y9_Spreadsheets_and_Calculators_25.gif Y9_Spreadsheets_and_Calculators_24.gif Y9_Spreadsheets_and_Calculators_04.gif Y9_Spreadsheets_and_Calculators_23.gif Y9_Spreadsheets_and_Calculators_11.gif 23000

Calculations can be carried out using the Y9_Spreadsheets_and_Calculators_23.gif button.

e.g. To calculate (3.65 × 104) × (2.67 × 105) press:

Y9_Spreadsheets_and_Calculators_04.gif Y9_Spreadsheets_and_Calculators_24.gif Y9_Spreadsheets_and_Calculators_22.gif Y9_Spreadsheets_and_Calculators_26.gif Y9_Spreadsheets_and_Calculators_23.gif Y9_Spreadsheets_and_Calculators_11.gif Y9_Spreadsheets_and_Calculators_27.gif Y9_Spreadsheets_and_Calculators_25.gif Y9_Spreadsheets_and_Calculators_24.gif Y9_Spreadsheets_and_Calculators_22.gif Y9_Spreadsheets_and_Calculators_06.gif Y9_Spreadsheets_and_Calculators_23.gif Y9_Spreadsheets_and_Calculators_26.gif Y9_Spreadsheets_and_Calculators_07.gif 9745500000 = 9.7455 × 109

In earlier years you may have studied the following calculator operations:

Basic Operations

Calculators know about the order that calculations are carried out. i.e. BEDMAS

e.g. Calculate 35 + 4 × 27 on a calculator. Press: Y9_Spreadsheets_and_Calculators_04.gif Y9_Spreadsheets_and_Calculators_26.gif Y9_Spreadsheets_and_Calculators_05.gif Y9_Spreadsheets_and_Calculators_11.gif Y9_Spreadsheets_and_Calculators_27.gif Y9_Spreadsheets_and_Calculators_25.gif Y9_Spreadsheets_and_Calculators_07.gif 143


Some calculators do not round numbers. e.g. Y9_Spreadsheets_and_Calculators_25.gif Y9_Spreadsheets_and_Calculators_15.gif Y9_Spreadsheets_and_Calculators_04.gif gives 0.666666666. This is called truncating.

Some calculators round numbers up or down e.g. Y9_Spreadsheets_and_Calculators_25.gif Y9_Spreadsheets_and_Calculators_15.gif Y9_Spreadsheets_and_Calculators_04.gif gives 0.666666667. This is called rounding.
This number is rounded to 9 decimal places as there are 9 digits after the decimal point.

Rounding Rules

If the digit to the right of the rounded digit is between 0 and 4. The rounded digit stays the same.
If the digit to the right of the rounded digit is 5 or above. The rounded digit has ONE added.

Square roots

To find the square root of a number use this key e.g. To find the square root of 36, press Y9_Spreadsheets_and_Calculators_17.gif Y9_Spreadsheets_and_Calculators_04.gifY9_Spreadsheets_and_Calculators_22.gif calcequals.gif 6

Square roots are often not whole numbers e.g. Y9_Spreadsheets_and_Calculators_17.gif Y9_Spreadsheets_and_Calculators_04.gif Y9_Spreadsheets_and_Calculators_06.gif Y9_Spreadsheets_and_Calculators_07.gif 6.08276253


The two brackets keys Y9_Spreadsheets_and_Calculators_28.gif and Y9_Spreadsheets_and_Calculators_29.gif are useful for calculations involving fractions.

e.g. Calculate Y9_Spreadsheets_and_Calculators_30.gif Press: Y9_Spreadsheets_and_Calculators_04.gif Y9_Spreadsheets_and_Calculators_11.gif Y9_Spreadsheets_and_Calculators_15.gif Y9_Spreadsheets_and_Calculators_28.gif Y9_Spreadsheets_and_Calculators_26.gif Y9_Spreadsheets_and_Calculators_22.gif Y9_Spreadsheets_and_Calculators_05.gif Y9_Spreadsheets_and_Calculators_04.gif Y9_Spreadsheets_and_Calculators_13.gif Y9_Spreadsheets_and_Calculators_29.gif Y9_Spreadsheets_and_Calculators_07.gif 0.357894736


There is a button for an index of 2 (squared) Y9_Spreadsheets_and_Calculators_31.gif e.g. To find 1262, press Y9_Spreadsheets_and_Calculators_21.gif Y9_Spreadsheets_and_Calculators_25.gif Y9_Spreadsheets_and_Calculators_22.gif Y9_Spreadsheets_and_Calculators_31.gif Y9_Spreadsheets_and_Calculators_07.gif15876

To calculate with an index greater than 2 use the button Y9_Spreadsheets_and_Calculators_32.gif e.g. To find 234, press Y9_Spreadsheets_and_Calculators_25.gif Y9_Spreadsheets_and_Calculators_04.gif Y9_Spreadsheets_and_Calculators_32.gif Y9_Spreadsheets_and_Calculators_11.gif Y9_Spreadsheets_and_Calculators_07.gif 279841


Spreadsheets Y9_Spreadsheets_and_Calculators_33.gif

Computer programs such as Microsoft Office and Appleworks include a part called a spreadsheet
Spreadsheets can perform calculations using numbers and formulae arranged in rows and columns of cells
Words or numbers can be typed into the cells and calculations and other mathematical operations can be carried out.


The spreadsheet on the left shows only 32 cells. Some spreadsheets have thousands of cells.
Each cell has its own label. 
The one highlighted is cell B3.

The letters are at the top of the columns.
The numbers are at the beginning ofrows.

To move around a spreadsheet use the cursor or keys such as the TAB, pg up, pg down (the arrow keys)

Many features of a spreadsheet can be changed (formatted) using various menu commands:

  • The columns can be made wider
  • The rows can be made higher
  • Numbers and text in a cell can be made bold, coloured or a different size and font
  • Numbers and text in a cell can be put on the left hand side, the right hand side or in the centre.


Spreadsheets do calculations differently from normal maths equations and calculators. To do a calculation you have to type in the EQUALS sign first. To do multiplication use the * key and for division use the / key.




The values in cells can also be used in calculations.



Numbers and words in both rows and columns can be sorted into order.
To do the sort shown below BOTH columns must be selected and the spreadsheet told to sort on the B column.



Most spreadsheets will produce graphs, such as pie graphs, line graphs, bar graphs and scattergraphs.
See the units on Statisitcial Graphs for instructions and practice with these.