A spreadsheet is an application that allows the user to enter numbers and text into a table with rows and columns and perform calculations on them.
Computer modelling software enables the user to enter data and a set of rules, and then see what happens if bits of data are changed. A computer model of a school's budget, for example, might show that if an extra teacher is hired, the school will run out of money before the end of the term.
Computers models of mathematical data such as budgets are usually done using a spreadsheet a program that processes datadata: information which has been organised or presented for analysis and performs calculations.
How spreadsheets work
A spreadsheet [spreadsheet: An application that allows the user to enter numbers and text into a table with rows and columns and perform calculations on them. ] appears as a grid or table divided into rows and columns. Each cell in the grid has a cell address or reference, for example C5 means column C row 5. A range of cells can be referred to as a single unit, for example E4:E12 means all the cells from E4 to E12 inclusive.
Cells can contain numbers, text or a formula.
Here's a simple example which you can try out on your computer at home or school.
A grocer uses a mobile shop to sell groceries to customers who live a long way from the shops. He uses a spreadsheet to keep a record of the daily sales:
Daily sales
| A | B | C | D | E | |
|---|---|---|---|---|---|
| 1 | Monday | 12/12/99 | |||
| 2 | Number | ||||
| 3 | Unit | sold | Price | Sales | |
| 4 | Apples | kg | 7 | £0.70 | £4.90 |
| 5 | Potatoes | 25 kg | 8 | £6.00 | £48.00 |
| 6 | Oranges | kg | 6 | £0.90 | £5.40 |
| 7 | Carrots | 25 kg | 8 | £8.50 | £68.00 |
| 8 | Sprouts | kg | 4 | £1.40 | £5.60 |
| 9 | Cabbage | kg | 6 | £0.70 | £4.20 |
| 10 | Onions | kg | 9 | £0.56 | £5.04 |
| 11 | |||||
| 12 | Total | £141.14 |
- Cells A1 and B1 contain the day and date.
- Column A and B contain text.
- Column C contains the number sold and column D contains the price in currency format.
- Column E contains a formula to work out the sales (the formulae are hidden - only the results are displayed). For example, cell E4 contains the formula =C4×D4; cell E5 contains the formula =C5×D5 and so on.
- Cell E12 contains a formula to add the numbers from E4 to E10. This could be entered =SUM(E4:E10). It is much better to use this formula than =E4+E5+E6+E7+E8+E9+E10 which will give the same result but is difficult to read and it is easy to make a mistake. Note that you should only use the =SUM function when adding a range of cells.
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