# ICT 9: Introduction to Spreadsheets

A spreadsheet is an interactive computer application program for organization and analysis of text and numerical data in tabular form. Data is stored in a cell which is referenced by rows and columns. Each cell can contain a text, a number or a formula that automatically calculates and displays a value based on the contents of other cells.

Spreadsheet users can make changes in any stored value and observe the effects on calculated values. This makes the spreadsheet useful for “what-if” analysis since many cases can be rapidly investigated without tedious manual recalculation. Modern spreadsheets allow multiple interacting sheets and can display data in graphical form.

In addition to the fundamental operations of arithmetic and mathematical functions, modern spreadsheets provide built-in functions for common financial and statistical operations. Such calculations as sum and average can be applied to tabular data with a pre-programmed function in a formula. Spreadsheet programs also provide conditional expressions, functions to convert between text and numbers, and functions that operate on strings of text.

Spreadsheets have now replaced paper-based systems throughout the business world. Although they were first developed for accounting or bookkeeping tasks, they now are used extensively in any context where tabular lists are built, sorted and shared.

Excel now has the largest market share on the Windows and Macintosh platforms. Google Spreadsheets is a free web-based alternative to Excel.

A spreadsheet consists of a table of cells arranged into rows and columns. Columns are normally represented by letters (e.g. “A”, “B”, “C”), while rows are normally represented by numbers (1, 2, 3). A single cell can be referred to by addressing its row and column, such as “C10” for instance. Additionally, spreadsheets have the concept of a range, a group of cells, normally contiguous. For instance, one can refer to the first ten cells in the first column with the range “A1:A10”.

In modern spreadsheet applications, several spreadsheets are gathered together to form a workbook. A workbook is physically represented by a file containing all the data for the workbook, the sheets and the cells with the sheets. Worksheets are normally represented by tabs that flip between pages. Cells in a multi-sheet workbook add the sheet name to their reference, such as “Sheet 1!C10” for instance.

Users interact with sheets primarily through the cells. A given cell can hold data by simply entering values or entering formulas. Formulas are created by preceding the text with an equals sign, such as =5*3 to yield 15 in the cell.

A key feature of spreadsheets is the ability for a formula to refer to the contents of other cells, which may in turn be the result of a formula. To make such a formula, one simply replaces a number with a cell reference. For instance, the formula =5*C10 would produce the result of multiplying the value in cell C10 by the number 5. If C10 holds the value 3 the result will be 15. If the value of C10 is changed to 5, the result will automatically be updated to 25.

In addition, C10 might also hold its own formula referring to other cells. The ability to chain formulas together is what gives a spreadsheet its power. Many problems can be broken down into a series of individual mathematical step, and these can be assigned to individual formulas in cells. Some of these formulas can apply to ranges as well, like the SUM function that adds up all the numbers within a range.

Spreadsheets share many principles and traits of databases, but spreadsheets and databases are not the same thing. In short, spreadsheets lack the relational structure of databases.

Tutorials

To gain basic proficiency of spreadsheets, you will follow a series of Google Spreadsheet tutorials and complete the task on the last page of each section. These practice problems are labeled as Challenge! The purpose of these exercises is to help you apply and reinforce the main concepts that you have learned. There will be a quiz at the start of each class based on these concepts.

Note: Remember to share the Google Spreadsheet with the teacher for marking.