Spreadsheets (formulas, charts, modelling) - ICT IGCSE Study Notes

Think of a spreadsheet like a giant, super-smart grid of boxes, called cells, on your computer screen. Each cell is like a tiny container where you can put numbers, words, or even special instructions.

• Formulas: These are like secret commands you type into a cell to tell the spreadsheet to do a calculation. For example, you could tell it to add two numbers together, find the average of a list, or even check if a number is bigger than another. It's like having a super-fast calculator built right into your grid!
• Charts (or Graphs): Imagine you have a long list of numbers, like how many ice creams were sold each day. Charts take these numbers and turn them into colourful pictures, like bar graphs or pie charts. This makes it super easy to see patterns, compare things, and understand the data much faster than just looking at rows and rows of numbers. It's like turning a boring book into an exciting comic strip!
• Modelling: This is like playing a 'what if' game with your numbers. You can change one number in your spreadsheet and immediately see how it affects all the other calculations and even your charts. For example, 'What if we sold 100 more ice creams? How much more money would we make?' Spreadsheets help you predict outcomes without actually having to do it in real life first.

Let's imagine you're running a small lemonade stand. You sell lemonade for $1 a cup, and it costs you 30 cents to make each cup.

1. Setting up the spreadsheet: You'd open your spreadsheet and label some columns like 'Cups Sold', 'Income (Money In)', 'Cost (Money Out)', and 'Profit (Money Left Over)'.
2. Using Formulas: If you sold 50 cups, you'd type '50' into the 'Cups Sold' cell. Then, in the 'Income' cell, you'd type a formula like =A2*1 (meaning, 'take the number in cell A2 and multiply it by 1'). In the 'Cost' cell, you'd type =A2*0.30. Finally, for 'Profit', you'd type =B2-C2 (meaning, 'take Income and subtract Cost'). The spreadsheet instantly calculates your income, cost, and profit!
3. Creating a Chart: You could then select your 'Cups Sold' and 'Profit' numbers and tell the spreadsheet to make a line chart. This chart would visually show you how your profit goes up as you sell more cups, making it super clear to understand.
4. Modelling ('What If'): Now for the fun part! What if you wanted to see what happens if you sell 70 cups instead of 50? You just change the '50' to '70' in the 'Cups Sold' cell, and instantly all your income, cost, profit, and even your chart update automatically! You don't have to do any calculations yourself. This helps you plan for the future without actually having to sell any more lemonade yet.