In introducing Spreadsheets we want you to learn to build a numberline by using a rule (a formula). We begin with a simple rule that you can copy and paste into the entire numberline. Then we want to add an input from another cell into the rule to give you a chance to change the numberline. And finally you build a rule that lets you change not only the input number but the operation so that you can build any numberline you want. Remember that you have three ideas in functional thinking, an input, an output, and a rule to change the input into the output.