# Formulas, Functions - Informatics and Information Technology

## Formulas

Microsoft Office Excel processes data using formulas and built-in standard functions.

Formula - equation or expression. In the cell of the spreadsheet, the formula is the entered expression, always starting with the equal sign "= and contains further constants (numbers), operators, functions, and references-the addresses of cells. The cell addresses entered in the formula determine how the cell value depends on the data in the other cells of the current sheet, sheets of the same book, or other books.

For example, in cell C5, the formula = A4 * D7 will multiply the data from cell A 4 by the data from cell D1. In the sheet cell, the formula is visible only at the time of input or editing, and after entering the cell displays the result of the calculations. When the table cursor selects a cell with a formula, you can see it in the formula bar.

The constant is a ready (unalterable, constant) value that is entered in the cell: text, integer and decimal numbers (including interest and monetary formats), dates, and time. For example, the number 210, the date 09/04/2011, and the text Total - constants, and the expressions = (35 + 590) * 23 and = 0.13 * CУMM (C9: D29) - formulas, which include numerical constants of 35,590, 23 and 0,13. The formulas themselves are not constants.

Operators define actions in the formula (addition, multiplication, division, comparison, and union). Arithmetic operators +, -, *,/enter plus, minus, multiply, divide, for example: = (B4 + 25 * C4)/(D5-F5). The percent operator% is written close to the number or address of the cell and corresponds to a division by 100. The formula = (1 + 5%) computes the value of 105%, and the formula = C5 * (1 + 5%) is equivalent to = C5 * 1.05 and calculates 105 % of the number in cell C5. The exponentiation operator Λ ("cap") is on the 6angl key. For example, the formula = 3 ^ 4 means 34 and will return the value of 81. The term return with respect to formulas and functions of table processing, means "output as a cell value". The data, formulas, functions are typed and entered and after calculation the result is returned - number, text.

Comparison Operators. = (equal), & lt; (less), & gt; (more), & lt; = (less than or equal to), & gt; = (greater than or equal to), & lt; & gt; (not equal) - are used as conditions and criteria for logical and statistical functions.

The reference operators are: a colon between the addresses of the first and last cell of the rectangular range (C9: D29) and a semicolon that separates several parameters, for example, CPAN (B9: B29; D9: D29; 200) .

The syntax of writing a formula specifies a sequence of calculations, and in functions - the rules for writing their names and given arguments (variables). By default, Excel calculates the formula from left to right, starting with an equal sign, and returns a number. The formula = 5 + 2 * 3 returns the number 11, but the formula = (5 + 2) * 3 with the same numbers first computes the value 7 in parentheses, then multiplies by 3 and returns the number 21.

A cell containing a formula with a reference to an address is called an dependent cell, because its value depends on the value of the other cell to which it refers. An independent cell - a cell with a number or a formula of numerical constants - does not contain address-references to other cells.

For example, a cell with the formula = 2 * 2 is independent, and a cell with the formula = B9 * K15 is dependent and recalculates the value again if you change the data in cell K15, to which the formula refers. Conversion of values ​​in dependent cells when changing data in independent cells is a powerful automation of Excel.

## Functions

The word function (lat. functio - execution) in the usual sense means activity, duty, work, role.

In mathematics the function is a variable dependent on the change of the independent variable - of the argument. The function can be represented by the correspondence y = f ( x), and also a formula, a table, a graph, a diagram.

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