If you mean in Excel, yes: you must always start a formula with an equal sign.
A formula with an equal sign
It has the same meaning as an equals sign anywhere else in mathematics.
It is generally positive(+) or negative(-).For example: speed = distance/time.
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.
If you mean in Excel, yes: you must always start a formula with an equal sign.
equal sign (=)
an equal sign =
An equal sign because in order for the formula to go through correctly it has to have an (=)
Equal sign
Type = (equal sign) to begin a formula on a spreadsheet.
equal sign
Equal sign (=)
equal sign (=)
A formula must begin with the equal sign (=).
an equal sign =
A formula with an equal sign