You already know how to add up numbers with SUM and find an average. Today you'll teach your spreadsheet to make decisions and to count and total only the rows that matter. These logical formulas are what turn a plain list of project data into a sheet that answers real questions about your Something Real project.
Think of one yes/no question your project data could answer. For example: "Is each item under budget?" or "Did I hit my target this week?" How would you decide the answer if you were checking it by hand, one row at a time?
Open with a 30-second recap of the logical-formula work students did in the Introduction course (a single IF). Ask two or three students to say their warm-up question aloud before the demo.
Cross-curricular feed: the SUMIF / COUNTIF logic here directly scaffolds data analysis for the Practical Achievement Task and any researched General Education Task. Flag this and set scaffolds_student_task: true for the Practical Achievement Task.
These are the logical functions you'll use today. Each one lets your sheet apply a rule instead of just recording a number.
| Concept | Why it matters | Example |
|---|---|---|
IF — checks one condition and returns one of two results: =IF(test, value_if_true, value_if_false) | Lets your sheet flag rows automatically instead of you eyeballing every row | In a project budget, =IF(D2>50,"Over","OK") labels each cost as Over or OK |
| Nested IF / IFS — chains more than two outcomes; IFS is a cleaner way to write the same logic in newer versions | Real decisions often have more than two answers (low / medium / high) | =IFS(D2>100,"High",D2>50,"Medium",TRUE,"Low") bands your event's match-day costs |
| SUMIF — adds up only the cells that meet a condition | Totals just one category of your project data without sorting first | =SUMIF(A2:A6,"Equipment",D2:D6) totals only the equipment costs |
| COUNTIF — counts how many cells meet a condition | Answers "how many of these happened?" in one formula | =COUNTIF(D2:D6,">50") counts how many costs are over €50 |
| AVERAGEIF — averages only the cells that meet a condition | Finds the average of one group while ignoring the rest | =AVERAGEIF(A2:A6,"Travel",D2:D6) gives the average travel cost |
| AI as Explainer — asking an AI "explain this formula at a level I can teach back" while you still type it yourself | You keep ownership of the work; AI helps you understand, not replace you | — |
Using AI as an Explainer is fine and useful. Ask it to explain what a formula does or why it gave the wrong answer, then write and check the formula yourself. If AI helped, add a one-line note to your file saying what you used it for.
Stress the COUNT vs COUNTA point when you reach COUNTIF: COUNTIF counts cells that match a condition, which is different from COUNT (numbers only) and COUNTA (any non-empty cell). Weaker readers should focus on IF and SUMIF; confident students can push into IFS.
You'll build a small worked example: a five-item project cost sheet, then add an IF flag, a SUMIF total, a COUNTIF count, and an AVERAGEIF average. This mirrors exactly what you'll then do with your own project data.
Demo the first IF live on the classroom screen, then let students work through the rest at their own pace while you circulate. Watch for students typing the formula into the wrong cell.
| Issue | Solution |
|---|---|
| My SUMIF or AVERAGEIF returns 0 or an error | Check the category text in your condition matches the spelling in the range exactly, including capital letters |
| COUNTIF gives the wrong number | Put the condition in quotes with the operator inside, like {{formula:=COUNTIF(D2:D6,">50")}}, and check your range covers all the rows |
| My IF shows the formula text instead of a result | Make sure the cell starts with {{formula:=}} and is not formatted as text — clear formatting and re-enter |
| Autofill changed a range I wanted to stay fixed | You'll fix this properly with absolute references later — for now, retype the formula in the cell it went wrong in |
The exact-match spelling issue in SUMIF is the most common blocker — head it off before students start their own data.
Circulate and check each student's formula against their own data. Confident students can add a nested IF or IFS with three or more bands as a stretch. Collect {{code:69_logical_formulas}} as the Key Assignment evidence for this lesson.
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