There are several possible tools in spreadsheet management which support deep-approach metacognitive problem solving. In the following, array formulas (AF) are introduced, one of the possible solutions. Array formulas are a long-existing feature of spreadsheets, but somehow they have never reached the status they deserve; the introduction of array handling without the complexity known in high level programming languages.

In general, we distinguish between two different kinds of array formulas and their combinations:

• the output by default is an array,
• the output by default is one value, but the default non-array argument(s) are substituted by an array(s),
• the combination of the types above, when both arguments and output values are non-default arrays.

There is one further group of array formulas which are worth mentioning: conditional array formulas. This group of formulas would fit into any of the three groups listed above; however, its significance from several different points of view gives it a special status. The great advantage of conditional array formulas is that they are able to substitute built-in problem-specific functions, which are highly program- and version dependent, and which are one of the blocks to an effective use of spreadsheet programs.