Spreadsheets earn their keep when they answer real questions: how many items moved, what was the average sale, which product lagged. Today you go deeper on the standard functions you already know (SUM, AVERAGE, MIN, MAX, COUNT) and add ROUND plus the COUNT family so a summary block can report clean, trustworthy numbers for your Something Real project.
Look at a column of product names and a column of units sold. If you ask the spreadsheet "how many products are on this list?", should it count the names or the numbers? Hold that thought: the answer is why COUNT and COUNTA are different tools.
Skim the quick-recap rows (you have met these before). Read the COUNT family and ROUND rows carefully: those are today's stretch.
| Concept | Why it matters | Example |
|---|---|---|
| SUM, AVERAGE, MIN, MAX (quick recap) — total, typical value, smallest, largest | A supervisor, club treasurer, or Work Experience mentor looks for these four first | Total units on a market stall; average hours on a Work Experience log; MIN/MAX shift length |
| COUNT vs COUNTA vs COUNTIF — COUNT tallies numbers only; COUNTA tallies every non-empty cell; COUNTIF tallies cells that meet a condition | Using COUNT on a list of names quietly returns 0 and looks like a broken sheet | COUNTA on product names = how many products; COUNTIF on units {{code:">=15"}} = how many products sold 15 or more |
| ROUND and nested functions — ROUND(value, digits) trims decimals; you can nest another function inside it | Money and averages need clean figures a reader can trust on paper or in a PDF | {{formula:=ROUND(AVERAGE(C2:C7), 2)}} gives a mean price to the nearest cent |
In the step-by-step you will build (or open) a short sales sheet for a student side hustle selling handmade accessories at a local market, then add a Summary statistics block. The practice sheet uses seven formulas; your own project sheet needs at least six. Independent practice applies the same pattern to real Something Real data and saves it as {{code:sm3_summary_block}}.
| Item | Units sold | Price (€) | Revenue (€) |
|---|---|---|---|
| Shamrock keyring | 24 | 3.50 | 84.00 |
| GAA crest badge | 18 | 4.00 | 72.00 |
| Name stickers pack | 12 | 5.50 | 66.00 |
| Phone grip | 8 | 6.00 | 48.00 |
| Lanyard | 15 | 2.50 | 37.50 |
| Sticker sheet | 30 | 2.00 | 60.00 |
Build a short market-stall sales sheet, add revenue formulas, format money cleanly, then create a Summary statistics block that uses SUM, AVERAGE, MIN, MAX, COUNTA, COUNTIF, and nested ROUND. The practice sheet builds seven formulas (your project sheet later needs at least six). Follow the tab for your spreadsheet app.
Starter option: your teacher may share a sheet with the headings and six product rows already entered. If so, save a copy as {{code:sm3_functions_practice}} in your sm3 folder and start at the revenue formula. Otherwise enter the table yourself first.
Use this table as a side reference while you build. Your teacher may freeze the class on the first row if several people hit the COUNT-on-text trap at once.
| Issue | Solution |
|---|---|
| My product count shows 0 | You probably used COUNT on a text column. Switch to COUNTA for names and labels. Use COUNT only when every cell you care about is a number. |
| {{code:#NAME?}} appears after I type a formula | Check the function spelling (AVERAGE not AVARAGE, COUNTA not COUNT A). Fix the name and press {{key:Enter}} again. |
| ROUND seems to do nothing, or shows too many decimals | The second argument is the number of decimal places. Use {{code:2}} for money-style figures, {{code:0}} for whole numbers. Nested form: {{formula:=ROUND(AVERAGE(C2:C7), 2)}}. |
| COUNTIF returns 0 when I expected matches | Check the condition in quotes, for example {{code:">=15"}}. Make sure you pointed COUNTIF at the numeric column, not the name column. |
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