By the end of this lesson, you'll solve:
"You have 30 students' marks in a column. Can you find the total and average with just two formulas instead of adding everything one by one by hand?"
Every Formula Starts with =
A spreadsheet formula is an instruction to calculate something. Every formula must begin with the equals sign (=). Without it, the spreadsheet treats your input as plain text and displays it as-is without calculating. After the =, you can use numbers, cell references, arithmetic operators (+, -, *, /), and function names. The magic: when the data in referenced cells changes, the formula result updates automatically.
Key Points
- 1Always start a formula with = (e.g., =5+3 displays 8, not "5+3")
- 2Use cell references instead of hardcoded numbers: =A2+B2 instead of =87+91
- 3If A2 changes from 87 to 90, =A2+B2 recalculates instantly — no manual update needed
- 4Arithmetic operators: + (add), - (subtract), * (multiply), / (divide)
- 5Use parentheses to control order of operations: =(A2+B2)/2 divides the sum by 2
Pro Tip
Always use cell references in formulas — NEVER type the actual numbers. If you write =87+91, you must retype the formula every time a mark changes. =C2+D2 updates by itself. This is the single most important habit in spreadsheet work!