In Calc: How do I search for an exact number?

When ~I search for 55, 556 will be highlighted because it contains 55. How do I search for an exact number?

If (!) 55 is a defined single number in a range of numbers (no text) you can SEARCH (FIND&REPLACE function) this way (regular expressions enabled):

^55$

The ^ means “begin of paragraph”, the $ means “end of paragraph”.

If you want to distinguish formulae or values, so you can choose one of these options:

The Find & Replace dialog has an option to search ‘Formulas’, ‘Values’, or ‘Notes’. This applies to any search, not just one using regular expressions. (source: Documentation/How Tos/Regular Expressions in Calc - Apache OpenOffice Wiki)

There’s also “Entire cells” checkbox under the “Find” box in Find & Replace.