Computers and calculators are the tools of modern mathematicians.

### Calculators

 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.

### Integers

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

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

-10

### Fractions

Some calculators have a fraction button  .

e.g. To calculate 34 + 89 press:

1 23 36 which means 12336

If your calculator does not have a fraction button press:

1.638888889 which is equivalent to 12336

### Roots

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

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

2

### Standard form

To enter a number in standard form into a calculator:

 Standard form Enter 2.3 × 104 into calculator 23000

Calculations can be carried out using the  button.

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

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:        143

Rounding

Some calculators do not round numbers. e.g.    gives 0.666666666. This is called truncating.

Some calculators round numbers up or down e.g.    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    6

Square roots are often not whole numbers e.g.     6.08276253

Brackets

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

e.g. Calculate  Press:            0.357894736

Indices

There is a button for an index of 2 (squared)  e.g. To find 1262, press     15876

To calculate with an index greater than 2 use the button  e.g. To find 234, press      279841

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.

Calculations

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.

Formulae

The values in cells can also be used in calculations.

Sorting

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.

Graphing

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.