Formulas and Cell References

Everything Starts with =

A formula begins with = and computes a value:

=2+3        ->  5
=A1+B1      ->  adds two cells
=A1*0.18    ->  18% of A1

Operators: + - * / ^ and parentheses for grouping - same math rules as everywhere.

Cell References

• Relative A1 - adjusts when copied (the classic pattern).
• Absolute $A$1 - locked; never changes when copied.
• Mixed $A1 or A$1 - locks only the column or the row.

Press F4 while editing a reference to cycle Relative → Absolute → Mixed.

Why Relative/Absolute Matter

Copy =B2*$E$1 down and the B2 slides with each row while $E$1 stays put - exactly what a commission table needs.

Referencing Other Sheets and Files

=Sheet2!A1              # same workbook, other sheet
=[Budget.xlsx]2026!C10   # another open file

Common Mistakes

• Leading = missing - Excel treats it as text.
• Formula shows the text but not a result - check the cell is not formatted as Text.
• #REF! means the referenced cell was deleted; #DIV/0! means divide by zero.

Key Points

• Formulas connect cells - change an input and results update.
• F4 toggles $ locks; use them so copies behave.
• Read error codes instead of panicking - each one tells you what broke.