Third graders (and students in other grades as well) are often asked to identify patterns in a series of numbers. For example, given the following series of numbers: 7, 10, 13, 16, students might be asked to identify the next two numbers in the series or describe what mathematical “rule” is creating the pattern (in this case, the rule is “adding 3″). So I figured this was a perfect opportunity to teach the students in Ms. Boone’s class at Chamberlayne Elementary about spreadsheets and formulas. I gave them a Numbers template that you can download by clicking here (I just adjusted the size of the cells and fonts). I told them to enter any 2-digit number into cell B2. Then in cell C2 we wrote a formula “=B2 + 3″ and pressed the Enter key. The answer automatically appeared in the cell. Then I showed them how they could click in the cell and drag the little dot in the lower right corner to fill in the neighboring cells and create a pattern. Next they wrote the rule in the box. We continued in a similar manner writing formulas for subtraction, multiplication (use *), and division (use /). Once the students understood how to write formulas, I let them write a formula of their own. Then a partner had to enter a number and see what the “secret” formula did to that number. Their goal was to try to identify the formula or rule that was creating the pattern. Some students discovered that certain numbers (like 0 or 1) were very helpful in figuring it out!
