📎 This article includes 1 downloadable practice file ↓
In this article
This is where Excel stops being a table and starts being a calculator that never gets tired. Every formula starts with an equals sign, and the best formulas don’t contain numbers at all: they point at cells, so when the data changes, the answer changes with it.
Your first formula
Click an empty cell, type =2+3 and press Enter. The cell shows 5; the formula bar shows =2+3. That’s the core idea: the cell shows the result, the formula bar shows the formula.
| Operator | Meaning | Example | Result |
|---|---|---|---|
| + | Add | =120+80 |
200 |
| – | Subtract | =500-120 |
380 |
| * | Multiply | =12*60 |
720 |
| / | Divide | =900/4 |
225 |
| ^ | Power | =10^2 |
100 |
| % | Percent | =2000*18% |
360 |
| & | Join text | ="Hello "&"Ravi" |
Hello Ravi |
Order of operations
Excel does brackets first, then powers, then multiply and divide, then add and subtract. So =2+3*4 is 14, not 20. Use brackets when you mean something else: =(2+3)*4 is 20. When in doubt, add brackets; they never hurt.
Use cell references, not numbers
A shop bill: Qty in column B, Rate in column C.
| A | B | C | D | |
|---|---|---|---|---|
| 1 | Item | Qty | Rate | Amount |
| 2 | Notebook A5 | 12 | 60 | =B2*C2 → 720 |
| 3 | Gel pen (5) | 6 | 75 | =B3*C3 → 450 |
Type =B2*C2 once. You can type the addresses, or type = then click B2, type *, click C2, press Enter. Clicking avoids typos.
Now change the quantity in B2 to 15: the amount updates to 900 instantly. If you had typed =12*60, it wouldn’t.
Copy the formula down
Select D2 and double-click the fill handle (or drag it down). Excel copies the formula to each row and adjusts the references: D3 becomes =B3*C3, D4 becomes =B4*C4. These are called relative references. Lesson 11 covers when you need them to stay fixed with $.
Discount, GST and grand total
Put rates in their own cells, never inside formulas:
B7 (GST rate): 18%
B8 (Discount): 5%
D6 (Total): =D2+D3+D4+D5 ' or =SUM(D2:D5), Lesson 5
D7 (Discount): =D6*B8
D8 (GST): =(D6-D7)*B7
D9 (Grand total):=D6-D7+D8Next year the GST rate changes? Edit B7 and the whole bill updates. That’s the reason rates live in cells.
Formulas across sheets
Refer to another sheet with its name and an exclamation mark: =Rates!B2. If the sheet name has spaces, Excel adds quotes: ='GST Rates'!B2. Easiest: type =, click the other sheet’s tab, click the cell, press Enter.
Error values you’ll meet
| Error | Usual cause |
|---|---|
| #DIV/0! | Dividing by zero or an empty cell |
| #VALUE! | Maths on text, e.g. a “number” typed with a space |
| #NAME? | Misspelt function or missing quotes around text |
| #REF! | The formula pointed at a cell that was deleted |
| ##### | Not an error: the column is too narrow |
Where beginners go wrong
| Mistake | Fix |
|---|---|
| Forgetting the = sign | Excel stores the text “B2*C2” |
Typing numbers into formulas (=D6*0.18) |
Point to a rate cell instead |
| Typing a result over a formula | The cell stops updating; check the formula bar |
| Using x for multiply | Use * |
Practice
Download this lesson’s workbook below. It has a 4-item shop bill with GST and discount rates, plus order-of-operations questions. Type your answers in the yellow column; the Check column turns green when you’re right, and the Answers sheet shows a working formula for every task.
📎 Practice files for this article
- 📗Lesson 4 practice workbookA shop bill: amounts, totals, discount, GST and grand total, plus order-of-operations questions.⬇ XLSX · 13 KB
Free to use for learning. Files with macros (.bas) are plain text — import them with Alt+F11 → File → Import File, and always test on a copy.
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