Without it, Excel will treat what you type in as a number, date or text. What you type will then literally appear in the cell. All functions start with letters. If the first thing you type is a letter, then it would be treated as text. The equals sign tells Excel to do the calculation that follows it. If you try typing any formula or function without an equals sign it will just appear in the cell and not do a calculation.
If you mean in Excel, yes: you must always start a formula with an equal sign.
equal sign (=)
Equal sign (=)
equal sign
Formulas must start with the equal sign (=).
The first character in a cell to indicate a formula is the equal sign (=).
An equal sign because in order for the formula to go through correctly it has to have an (=)
In most spreadsheet programs like Excel, you typically start a formula with an equal sign (=) to indicate that the following characters are part of a formula and should be calculated.
If you mean "spreadsheet program", not necessarily. That's a standard used in Excel; in older spreadsheets, such as Lotus 1-2-3, the formula used to start with a plus sign instead. A minus could be used as well, if it was appropriate for the formula. However, nowadays it seems to have become quite standard for formulae to start with an equal sign.
equal sign (=)
The equal sign in Excel is used to start a formula. All formulas begin with the equals sign. It can also be used for comparing things. In the following example, the first equals sign is starting the formula and the second one is comparing cell A2 and B2: =A2=B2
You must start all formulas with an equal (=) sign. This symbol will tell Excel that you want to write a flormula.