Excel Lesson 3 USING FORMULAS & FUNCTIONS 1
OBJECTIVES Enter formulas in a worksheet Understand cell references Copy formulas Use functions Review and edit formulas 2
INTRODUCTION The value of a spreadsheet program such as Excel, is the ability to perform simple and complex calculations in a worksheet. In this lesson you will learn how to: Enter Formulas Perform Calculations Introduction to predefined formulas: mathematical, statistical, financial and more The commands for working with formulas and functions are located on the Formulas tab on the Ribbon 3
ENTERING FORMULAS A formula is a set of instructions used to perform calculations on values in a worksheet. Formulas can set up a relationship between two or more cells. An Excel formula must begin with the equal sign (=) and is followed by the set of instructions for completing a calculation. 4
A formula s instructions contain operators and the values you want calculated. An operator is a sign or symbol that indicated what calculation is to be performed. The most commonly used operators are the arithmetic operators used for addition, subtraction, multiplication, division and exponentiation. 5
FOR EXAMPLE: The formula =3+2 entered in a cell will result in the value of 5 in the cell the formula was entered. Press Enter In this case the values are constants, which are numbers entered directly into a formula that do not change. 6
More commonly, formulas in Excel use cell references to identify the cells containing the values you want to use in the formula. C1 contains the value of 3, D1 contains the value of 2, and E1 has the formula to add C1 and D1 together. If the value in C1 or D1 changes, the total will automatically adjust. 7
You can also use a combination of constants and cell references in a formula. If we knew that 5 was the constant (never changing) we can write the formula in D1 to show =C1+5. C1 is a cell reference that could change, while D1 will always be using number 5 consistently. The (+) is the operator, in this cell adding 5 to the contents of Cell C1. 8
ARITHMETIC OPERATORS OPERATOR OPERATION EXAMPLE DESCRIPTION + (PLUS SIGN) ADDITION A7+D9 Adds the values in cells A7 and D9 - (MINUS SIGN) SUBTRACTION A7-D9 Subtracts the value in D9 from the value in A7 * (ASTERISK) MULTIPLICATION A7*D9 Multiplies the values in A7 and D9 / (FORWARD SLASH DIVISION A7/D9 Divides the value in A7 by the value in D9 % (PERCENT SIGN) PERCENT A7*D9% Calculates 25% of the value in A7 ^ (CARET) EXPONENTIATION A7^4 Raises the value in A7 to the fourth power 9
If you want to add the values of cells B8 through G8, you could enter it as: =B8+C8+D8+E8+F8+G8 and press Enter, or You could also select the H8 cell, type in the = sign, click on the B8 cell, type +, click on the C8 cell, type +, and so on. Note: 2010 Excel will display each cell reference in the formula and the border of the corresponding cell in the worksheet with a distinct color. 10
ORDER OF OPERATIONS Some formulas will contain more than one arithmetic operator. Excel follows the order of operations, a specific sequence used to calculate the value of a formula. Excel performs calculations in the normal algebraic priority, which means the calculations are executed from left to right in the following order: 1. Exponentiation (^) 2. Multiplication (*) or division (/) 3. Addition (+) or subtraction (-) 11
If you want to change the order of operations, you use parentheses to group expressions in your formula. The expression inside the parentheses gets calculated first. This example below shows how the order of operations can affect the resulting value of a formula. 3 + 7 * 2 = 17 Multiplication calculation is done first, then addition: 7 X 2 = 14 + 3 = 17 (3 + 7) * 2 = 20 Parentheses calculation is done first: 3 + 7 = 10 X 2 = 20 12
Using comparison operators will compare two values to obtain a logical value, either TRUE or FALSE. OPERATOR MEANING EXAMPLE TRUE FALSE = Equal to A7=D9 The values in cell A7 and D9 are equal The two values are not equal > Greater than A7>D9 < Less than A7<D9 >= <= <> Greater than or equal to Less than or equal to Not equal to A7>=D9 A7<=D9 A7<>D9 The value in cell A7 is greater than the value in cell D9; The value in cell A7 is less than the value in call D9 The value in cell A7 is greater than or equal to cell D9 The value in cell A7 is less than or equal to the value in cell D9 The value in cell A7 is not equal to the value in cell D9 The value in cell A7 if less than or equal to the value in cell D9 The value in cell A7 is greater than or equal to the value in cell D9 The value is cell A7 is less than the value in cell D9 The value in cell A7 is greater than the value in cell D9 The value in cell A7 is equal to the value in cell D9 13
UNDERSTANDING CELL REFERENCES & COPYING FORMULAS 14
Auto Fill is a feature that you can use to automatically fill in worksheet data in any direction. You can use it to quickly copy a formula down in a column or across a row by dragging the fill handle of the cell containing the formula. A fill handle is a little black square in the lower-right corner of the selected cell. When you point at the fill handle, the pointer turns into a black cross that you can click and drag over adjacent cells, as far as you want to copy the formula. 15
When you finish using the fill handle, the AutoFill Options button is displayed next to the fill handle. You can click it to open a menu to choose to fill only the formatting or to fill without formatting. Copying formulas is not as straightforward as coping formatting or text entries. When you copy a formula to another location in a worksheet, it can change depending on what type of cell reference it contains. 16
A relative reference means the reference to a cell changes in relation to the location of the formula. For example: If you enter the formula in cell B4: =B2+B3, you are asking it to total cells B2 and B3. If you copy the same formula into C4, Excel adjusts the formula to add the values in the two cells immediately above C4. This saves you time from having to type the formula each time. 17
An absolute reference is a permanent reference to a cell and does not change in relation to the location of the formula. You can type an absolute reference by typing a dollar sign before the column letter and before the row number ($B$2+$B$3). If you copy a formula with the absolute reference from one cell to another, it stays exactly the same. This can be useful when you want the same cell repeatedly in different formulas or use the same formula in a different location in the workbook. Original formula with absolute cell reference Absolute cell reference does not change when copied 18
Sometimes you may only want one part of the formula to change, and another part to stay the same. A mixed reference contains both relative and absolute cell references. When you copy a formula with mixed references, the relative reference changes based on the new location, but the absolute reference does not. Original formula with mixed cell references Relative column references change when formula is copied; absolute row reference did not 19
USING FUNCTIONS Excel provides built-in formulas, called functions, that enable you to perform complex calculations easily. Instead of entering all the cell references, you can use a function in a formula to tell Excel to perform a calculation. For example: The SUM function totals the values in a range of cells, which is easier that typing each cell separately. 20
A function must follow a set of established rules called syntax, that specifies how the function must be entered. The standard syntax for Excel is: =Function name (argument 1, argument 2 ) Most functions require an argument. An argument, which follows the function name and is enclosed in parentheses, refers to the text, numbers, or cell references on which the function is to be performed. For example: in the function =SUM(B2:B11), the range B2:B11 is the argument. If you have more than one argument in a function, you separate it with a comma. There are hundreds of functions available in Excel, and they are organized into categories, based on their general purpose, such as Financial, Date and Time, and Statistical. 21
Examples of functions FUNCTION CATEGORY RETURNS EXAMPLE OR LOWER DATE SQRT COUNT TBILLYIELD Logical Text Date & Time Math & Trig Statistical Financial TRUE if any argument is true; FALSE if none of the arguments are true All letters in the cell as lowercase The number that represents the date The square foot of the number in the argument The number of cells in a range that contain numbers The yield for a Treasury bill =OR(A8<100) returns TRUE if the value in 8A is less than 100 and FALSE if the value in A8 is greater than or equal to 100 =LOWER(A15) converts all the letters in A15 to lowercase =DATE(2014,5,12) returns 5/12/14 (when cell is formatted with General or Date format =SQRT(A6) calculates the square root of the value in A6 =COUNT(A2:A7) counts all the cells in the range that contain numbers =TBILLYIELD(A2,B2,C2) calculates the yield on a Treasury bill with a settlement date in A2, a maturity date in B2, and the price per $100 face value of C2 22
To quickly total a range of cells without manually typing the formula, you can use the SUM function. You can click the Sum button on the Home tab, in the Editing group, or The Formulas tab in the Function Library group. You usually do not need to even select a range. If you select a cell the right or below a range of numbers, Excel automatically includes that range in the formula. 23
When you click the Sum button arrow in the Function Library group, a menu of the most common statistical functions is displayed: The Average function returns the average of a set of values The Count Numbers function counts the number of cells in a range that contains numbers The Max function returns the largest value in a set of values The Min function returns the smallest value in a set of values You can also choose functions in other categories 24
You can also choose a function in the Insert Function button in the Function Library group on the Formulas tab to open the Insert Function dialog box. Search for a function List of function names Click to select a function category Syntax and description of selected function 25
Once you select a function in the Insert Function dialog box, or on the Ribbon, Excel opens the Function Arguments dialog box. Function Name Arguments Description of function Collapse button Description of active argument Formula result You can enter arguments for functions easily into the dialog box or click the collapse button to reduce the size of the dialog box temporarily and click the cells to be used as cell references in the argument. 26
REVIEWING & EDITING FORMULAS You may want to display the formulas in a worksheet, instead of the results, to check it for errors and accuracy, To display the formulas, click the Show Formulas button in the Formula Auditing group on the Formulas tab. 27
Sometimes you may need to troubleshoot an error in the formula. When you click the Error Checking button the Error Checking dialog box will open and help you resolve the problem. Location of error Description of error Options for resolving error Excel indicates when a formula you have entered results in an error by displaying an error value. This may look like #DIV/0! (indicating that the formula is divided by 0) 28
A cell with an error also displays a small diamond shape with an exclamation mark. By clicking on the arrow, it will display the type of error. If your cell contains a series of number symbols ######, the cell is not wide enough to display the results of the formula. By widening the column, the number will then be displayed. 29
List of common errors ERROR VALUE #DIV/0! #NA #NAME? #NULL! #NUM! #REF! #VALUE! DESCRIPTION OF ERROR Formula contains a number divided by zero or by a cell containing no value A value in the formula is not available in the worksheet Formula contains incorrect text; this often occurs when a function name is misspelled Formula specifies an intersection of two ranges which do not intersect Invalid use of a number in the formula, or when text is used in a formula or function's argument when a number is required Formula or function uses a cell reference that is no longer valid, which can occur if a cell or range of cells was deleted from the worksheet Incorrect data type used in the function or formula ##### Cell is not wide enough to display formula results 30
If you want to change or edit a formula, you can activate the cell containing the formula, type in the formula bar and press Enter. You can also double-click the cell containing the formula, or activate the cell and then press F2, which highlights each cell or range of cells with a different color so you can easily edit the formula in the cell. 31
What is on your mind? What did you learn that was new? What did you enjoy? What will you remember about this lesson? What can we do to make the lesson better? Special acknowledgements to the following for the use of information and photos for this Power Point presentation: Microsoft Office 2010 Fundamentals Laura Story & Dawna Walls Course Technology CENGAGE Learning - ISBN-13: 948-0-538-47989-9 and ISBN- 10: 0 538-47989-2 Google Images 32