Cells won't accept formula

Sometimes when I try to type a formula in a cell I get the text I typed instead of the formula. For example I might enter in A1, =B2. Instead of getting the data from B2, it reads =B2. I've looked at how the cell is formatted but can't get it to work. Thanks in advance.

The cells to which you are entering formulae are formatted as Text, ensure they are formatted to General before entering formulas.

If you have formulae as text you can convert them either by:

a) Highlighting them -> Edit -> Replace: What: = With: =
b) Highlighting them (1 column at a time) -> Data -> Text to Columns -> Finish