Teach Yourself Microsoft Excel Topic 6: Formulas and Functions

Transcription

1 Teach Yourself Microsoft Excel Topic 6: Formulas and Functions Last lesson you learnt how to enter and format text and numbers into a Microsoft Excel worksheet. In this lesson you will find out how to use formulas and functions in Microsoft Excel. Formulas One of the main functions of a spreadsheet is to perform calculations on the data that you have entered. These calculations are performed through the use of formulas. What distinguishes formulas from other data on the spreadsheet is that they must always begin with an equals sign (=). Formulas can contain numbers (values), cell references (E.g. A1), mathematical operators or text. Operators include plus (+), minus (-), divide (/) and multiply (*). Formula Components An example of a simple formula might look like: Equal sign Operators =(A4+C4)*6 Cell References Once you have entered the formula on a worksheet, the result or answer of the formula appears in the cell where it was entered. In the following exercise you will use data entry techniques that you learnt last week to insert the above text and number data into an Excel spreadsheet. After this you will enter formulas to work out profits calculated from your number data. Skills Check 6a Imagine that SPAN is running a local community inexpensive lunch-time Café. This cafe helps to raise money to keep SPAN running. It is run by four volunteers that occasionally get remuneration for their time but only if the café makes over $200 in a day anything over this is divided amongst the four volunteers. A table of data that could be used in a MS Excel worksheet for SPAN s Café food sales for one day of operating that can involve formulas to work out profit for the that day is shown below: Product Cost price Selling price Quantity sold Pasta $2.50 $ Coffee $0.75 $ Tea $0.25 $ Cake $1.50 $ Rolls $1.20 $ C:\Users\GerryKruyer\Documents\SPAN\ms-office\ms-excel\learning-tasks\level-2\task6\TYMSExcel6.docx Page 1

2 Before entering this data into a worksheet, it is important to plan how you want the data to appear to make it easy to understand and what calculations you would like to include. The best way to do this is to make a rough draft on paper. Proper planning of a spreadsheet in the early stages can save a lot of time later on. You do not have to include all of the data in your planning sketches this is up to you. The following could be a sketch of what I might draw up on paper for my MS Excel table design: Product Cost price Selling price Profit Quantity sold Total profit Pasta $2.50 $ Coffee $0.75 $ Tea $0.25 $ Cake $1.50 $ Rolls $1.20 $ Day s profit: Once you have an idea of what you want to calculate and how you want your spreadsheet set out, then you can start to enter your text and numbers. Follow these steps: 1. Open a new MS Excel workbook. 2. Type the data in the same cells as shown below remembering to leave any formatting including $ signs until steps 3 and 4 below. 3. You can use any font and font size that you like but whatever you use it should be easy to read. 4. Choose currency format for the Cost and Price leaving the two decimal places showing. 5. Make sure your columns are wide enough to see all data in the columns. It is a good idea to save your workbook after you have entered the necessary data. Then if you make an error, you do not have to waste time re-keying in the data. 6. Save your Excel workbook in your server space naming it Task-6a.xlsx C:\Users\GerryKruyer\Documents\SPAN\ms-office\ms-excel\learning-tasks\level-2\task6\TYMSExcel6.docx Page 2

3 Creating a Formula To calculate the Total Profit made from the sale of pasta, it would first be necessary to calculate the profit on each pasta meal. The formula would be: = Price - Cost = $5.50-$2.50 or = C6-B6 7. Click into cell D6 to select the cell where the formula is to be entered. You create a formula in Excel by firstly typing an equal sign (=) before the actual formula. 8. Type =C6-B6 Notice as you type the cell address in the formula, it highlights the formula itself in two colours on the worksheet and it colour codes the two cells involved in the calculation using those same two colours. This helps to prevent mistakes from being made. 9. Click to complete the process. Notice that even though the formula is still displayed on the Formula Bar, the result appears in the active cell. To calculate the total profit of all the pasta sales, the formula would be: = Profit x Qty. sold = $3.00*5 or = D6*E6 10. Click into cell F6 to select the cell where the formula is to be entered. 11. Type =D6*6E to enter an incorrect formula for the Total profit. 12. Click to complete the process. C:\Users\GerryKruyer\Documents\SPAN\ms-office\ms-excel\learning-tasks\level-2\task6\TYMSExcel6.docx Page 3

4 MS Excel automatically detects that there is an error in this formula and displays a dialog screen with suggested corrections as shown on the right: 13. Click to accept the correction. Now the total profit from the sale of pasta is shown in cell F6. As far as possible you should always use cell references rather than using numbers in your formulae. This will make it easier to make changes to your spreadsheet in the future. The only time you should include a number in a formula is if the number will never change in the future. For example, when you are multiplying by 24 to convert days to hours. 14. Enter formulae for the Profit and Total profit for the Coffee. You should get $43.75 for the Total profit. Tip: To save time typing in formulas, you can use your mouse to point and click on cells to build a formula. For example, to enter the formula =C8-B8 into cell D8: 1. Click D8 and type = 2. Point your mouse to C8 and Click. C8 is added to the equal sign in the formula bar and in cell D8. A marching ants border surrounds C8. 3. Type - 4. Point to B8 and Click. B8 is added to the - in the formula bar and in cell D8. A marching ants border surrounds cell B8. 5. Click or press Enter to conclude the formula in D8. Excel calculates the result and places it in cell D Use the method shown in the tip above to enter formulae for the Profit and Total profit for the tea. You should get $33.75 for the Total profit. Next we will deliberately enter an incorrect formula into cell D9 to calculate the profit on a piece of cake: 16. Click into cell D9 to select the cell where the formula is to be entered. 17. Type =C9*B9 to enter an incorrect formula for the Profit. (We should be using =C9-B9) 18. Click or press Enter to complete the process. Notice the tiny green triangle in the top-left corner in cell D9 that you may have made an error in your formula..this is a warning from Excel indicating 19. Click into cell D9 to select the cell 20. Notice that you get a warning symbol to the left of the cell:. C:\Users\GerryKruyer\Documents\SPAN\ms-office\ms-excel\learning-tasks\level-2\task6\TYMSExcel6.docx Page 4

5 21. Click on the warning symbol to reveal a list of choices as shown on the right: 22. Choose. The result of the formula appears in the cell. 23. Type in the other formulas as shown below: 24. Save the changes to your spreadsheet. Notes: 1/ To view all the formulas used in an Excel spreadsheet: Formulas tab in the Formula Auditing group. Repeat this again to return to the results. What if 2/ To check that you have included the correct cell reference in a formula double-click the formula. This will colour code each cell referenced in the formula and colour the borders of those referenced cells with the same colours as you saw earlier. Previously it was mentioned that you could have included the actual numbers in the formulas rather than cell references. The results would still be the same. The great advantage of a spreadsheet is the flexibility it provides by performing calculations automatically when certain variables change. For example, if you wanted to determine how much profit would be made if 8 pasta meals were sold, you just alter the appropriate quantity on the spreadsheet and, because the formula uses the cell reference (E6), it updates the Total profit cell (F6) automatically. The procedure of changing data causing results to update automatically is often referred to as What if analysis. In other words, what would happen if you sold 8 pasta meals? By using cell references in formulas, when things change you just have to edit the data in the worksheet and not the formula. 25. Click into cell E6 to select the quantity of pasta meals sold cell. 26. Type 8 to alter the quantity of pasta meals sold. 27. Click the Enter Box to accept the change. The Total profit figure for pasta changes automatically. C:\Users\GerryKruyer\Documents\SPAN\ms-office\ms-excel\learning-tasks\level-2\task6\TYMSExcel6.docx Page 5

6 AutoSum To calculate the Day s profit from all food and drinks sales you could type the following formula: =F6+F7+F8+F9+F10 This type of formula is relatively easy to enter when there are only a few cells involved but imagine if there were a thousand different products sold. The longer the formula, the more chance for an error to be made. A more efficient way to perform this calculation is through the use of the Home tab Editing Group. button in the Excel ribbon s The AutoSum button will automatically insert a formula in a selected cell to total either the cells above or to the left of the active cell. 28. Click into cell F11 to select the cell. 29. Click the button (not the arrow) to insert the formula. The formula =SUM(F6:F10) appears in the cell as shown on the right. This type of formula is referred to as a Function. (You will cover different Functions shortly.) Notice how a dotted line appears around the range of cells, including the data it expects to total. You also see a description of the Function structure just below the formula. The formula should be checked every time you use AutoSum as blanks or text in the middle of data may cause AutoSum to select the incorrect data for totalling. 30. Click the Enter Box to accept the formula. 31. Save the changes to your spreadsheet. Tip: Formulas that you type into a spreadsheet are performed in a specific order. This order is known as BIDMAS: Brackets Index Division Multiplication Addition Subtraction * 10 = 45 not 90 if the above maths rule is applied. Question 1. What is the result of the following calculations? a/ 30-2 * b/ 30-2 * (10 + 1) c/ / 2 d/ ( ) /2 C:\Users\GerryKruyer\Documents\SPAN\ms-office\ms-excel\learning-tasks\level-2\task6\TYMSExcel6.docx Page 6

7 AutoCalculate MS Excel includes a feature which can quickly display the sum, average, minimum, maximum or count of any range of cells. This feature is known as AutoCalculate. 32. Select the cell range E6:E10 Notice on the Status Bar (at the bottom of any window) that the Average, Count and Sum of selected cells are displayed on the right of the display bar as shown on the right: You can display other types of calculations on selected cells by clicking the right mouse button on the Status Bar. A pop-up menu appears displaying the types of calculations available. 33. Right-click on the Status Bar. The AutoCalculate menu appears as shown on the right: From this menu you can select the type of calculation to be displayed in the Status Bar. 34. Tick the Numerical Count. 35. Click elsewhere on the worksheet to cancel the AutoCalculate menu. Question 2. What is the average price of the five products? Functions AutoCalculate and AutoSum are different to the formulas you used earlier in this lesson. They are known as functions. These are built-in mathematical formulas. Excel includes over 100 built-in functions to perform specialist calculations. A function is a special type of formula and therefore must also start with an equal sign (=) similar to other formulas. A function has two important components: Function name Function arguments =Sum(F6:F10) The function name identifies the function while the function arguments identify data required for the calculation to be performed. Again, this can be either numbers or cell references but it is usually preferable to include cell references for flexibility. C:\Users\GerryKruyer\Documents\SPAN\ms-office\ms-excel\learning-tasks\level-2\task6\TYMSExcel6.docx Page 7

8 The SUM function shown above could have been entered as above or you could use: =SUM(F6,F7,F8,F9,F10) or you could use: =SUM(24,43.75,33.75,16,51.6) But it is preferable to use a cell range (F6:F10) with the SUM function if possible. Some simple functions which can be found by clicking on next to as shown on the right: =AVERAGE(F6:F10) =COUNT(F6:F10) =MAX(F6:F10) =MIN(F6:F10) the average of the arguments. the number of values in the arguments. the maximum value of the arguments. the minimum value of the arguments. Tip: When using any of these functions, you must check that the correct cell references are used in the function arguments. If they are incorrect then: 1. Drag your mouse across the cells that should be used in the arguments. 2. Click the Enter Box to accept the formula. Function Wizard As mentioned previously, MS Excel includes a large number of specialised functions. The most difficult part to using these functions is remembering the various components of the function's arguments. Excel includes a feature called the Function Wizard to assist users to create formulas involving functions. The Insert Function Wizard button appears on the Formula Bar. The functions included in Excel are grouped together in similar categories. One of these categories includes Logical functions. The IF function is a logical function which is useful for testing a cell s contents and displaying a value. For example: =IF(test, result if test is satisfied, result if test is not satisfied) Recall that the SPAN Café volunteers do get some remuneration if daily sales exceed $200. Thinking about how this could be coded in our café example it would be something like: IF(sales>$200, Bonus paid out, No bonus payment) They want the spreadsheet to automatically remind them if the sales figures exceed $200. An IF function can be used for this. 36. Click into cell E13 to select it and type in Bonus target 37. Click into cell F13 to select it and type in If the currency formatting in the cells above did not get used in cell F13, then copy the formatting from the cells above using the tool. C:\Users\GerryKruyer\Documents\SPAN\ms-office\ms-excel\learning-tasks\level-2\task6\TYMSExcel6.docx Page 8

9 This is the daily sales level above which a bonus will be paid to the SPAN Café volunteers. 39. Click into cell G13 to select it. The cell G13 is where you will enter an IF function that will result in one of two possible words being displayed: Bonus paid out or No bonus payment depending on the Day s profit value. 40. Click the Insert Function Wizard button in front of the Formula Bar. The Insert Function dialog box appears on screen as shown on the right: This dialog box displays the most recently used functions as well as providing you with the opportunity to search for the required function. As mentioned previously the IF function is categorised under Logical functions. All the functions in this category are listed. 41. Click on to display the function categories shown here: 42. Click on Logical to select this category. All the functions in this category are listed. I have circled them in red on the right: 43. Click on IF in the Select a Function: box to select it. Notice the IF function arguments and description at the bottom of the dialog box: 44. Click on OK to proceed with the Wizard. A dialog box appears below the Formula Bar requesting specific data for the IF function as shown on the right: C:\Users\GerryKruyer\Documents\SPAN\ms-office\ms-excel\learning-tasks\level-2\task6\TYMSExcel6.docx Page 9

10 The cursor is blinking in the Logical_test area of the dialog box waiting for the data to be entered. In this area you need to indicate what you are going to test. In this case you want to test whether the Day s profit figure in cell F11 exceeds the target figure of $200 stored in cell F13. Therefore, the logical test is to see if the contents of cell F11 is greater than F Type: F11>F13 You could also click into F11, type > and then click into F13 to enter the formula. Notice that the formula up to this stage is displayed in the Formula Bar. Also notice to the right of the dialog box that the word False appears to indicate the result of the logical test. In other words, F11 is not greater than F13. Now you have to indicate what happens if the day s profit is greater than the target level. 46. Press the Tab key to move to the Value_if_true text box. 47. Type Bonus paid out Now you have to indicate what happens if the daily sales are less than the target level. 48. Press the Tab key to move to the Value_if_false text box. Notice that Excel has inserted quotes around the words Bonus paid out. This indicates that this is treated as text. Type No bonus payment 49. Click on OK to complete the process. 50. Ensure that the formatting of cell G13 matches that of the other cells containing text. You probably need to make column G wider so that you can see all of the resulting text. The result of the function appears in cell G13 indicating that no bonus payment is payable as the Day s profit is below the target level. Once you create a function or formula you should change your data to test if your function s calculation is performed correctly. 51. Click in cell E7 to select it. 52. Type 45 as the Qty sold of coffee. 53. Click the Enter Box to accept the change. Notice that the words Bonus paid out now appears in cell G13. The IF function can also include formulas as well as displaying text. The bonus paid to each of the volunteers is the total daily sales figure exceeding the bonus target level divided by the number of volunteers working at the cafe. In our example there are four volunteers so you divide the total sales amount above $200 by 4. MS Excel can automatically work out this amount: 54. Click in cell E15 to select it. 55. Type: No. of volunteers 56. Press the Tab key to move to the next right cell. 57. Type: 4 for the number of volunteers. 58. Ensure that the formatting of cells E13 and F13 matches the rest of the spreadsheet making sure that cell F13 shows 4 and not Hint: Click on twice. 59. Press the Tab key to move to the next right cell. 60. Type: Volunteer s each paid: C:\Users\GerryKruyer\Documents\SPAN\ms-office\ms-excel\learning-tasks\level-2\task6\TYMSExcel6.docx Page 10

11 61. Format this cell to match the rest of the spreadsheet. 62. Make sure that the cell is wide enough so that you can see all of the text in this cell plus perhaps a bit more space on the left. 63. Press the Tab key to move to the next right cell. 64. Type = to indicate that you are about to enter a formula. Notice that in the Reference Area left of the Formula Bar the word IF appears. This is now a clickable button and indicates the last used function for quick access. 65. Click the button to display the IF dialog box. 66. Type (or using your mouse click in the formula): F11>F13 for the test to be performed again. 67. Press the Tab key to move to the Value_if_true text box. 68. Type (or using your mouse click in the formula): (F11-F13)/F15 i.e. Bonus profit No. volunteers You have now created a calculation to determine what the bonus would be to each volunteer if it was going to be paid. 69. Press the Tab key to move to the Value_if_false text box. 70. Type 0 to indicate no bonus payment. This will cause 0 to be displayed if the Days profit is below the Bonus target. Your Function Arguments dialog box should look like that shown on the right. Notice the added information that dialog box gives you. 71. Click on OK to complete the process. Notice a bonus figure of appears. 72. Format cell H15 to currency. The easiest way to do this is to use the tool. It should appear as $1.03. To test the function you have just created: 73. Click in cell E7 to select it. 74. Type: 25 as the Qty sold of coffee. (I know from earlier on in this lesson that this resulted in No bonus payment.) 75. Click the Enter Box to accept the change. The words No Bonus payment appears and the volunteers are each paid $0.00. C:\Users\GerryKruyer\Documents\SPAN\ms-office\ms-excel\learning-tasks\level-2\task6\TYMSExcel6.docx Page 11

12 Notes: i/ Instead of typing in 0 in to the Value_if_false text box above you could have used " " including both double-quote marks and this would have left the cell H15 empty (blank) if the volunteers did not get a bonus payment. I think I prefer to have $0.00 displayed rather than nothing. ii/ The Function Wizard dialog box can sometimes sit on top of the cells that you are trying to enter and you may not be able to remember their addresses. You can temporarily collapse the dialog box so that you can view the cells: Click to collapse the dialog box. Click to return the dialog box to the original size. 76. Validate your workbook: Make sure that every text entry in a cell is spelt correctly, every cell containing numeric data is correct and every cell containing a formula shows the correct result. Fix up all errors. 77. Type your name into one of the empty cells on the right. 78. Click, or Ctrl + S to save your workbook. 79. Click on the Page Layout tab and then click on the Orientation button. 80. Select Landscape so that when you do print your work it will fit onto less sheets of A4 paper. 81. Print your spreadsheet making sure that it fits onto one sheet of A Print out your formulas making sure it fits onto no more than 2 sheets of A Hand it to Mr Kruyer for ACFE purposes. Question 3. What are you doing when you are asked to validate your work? You have completed the section dealing with creating a formula in Excel. There is a homework exercise to complete. This exercise tests the Excel skills that you learnt so far in this course. C:\Users\GerryKruyer\Documents\SPAN\ms-office\ms-excel\learning-tasks\level-2\task6\TYMSExcel6.docx Page 12

13 Prove to Mr Kruyer that you have Learnt Excel Skills Create a new Microsoft Excel worksheet. The following worksheet is used to record the performance of SPAN Football Club players. It performs various statistics on the players goal scoring as well as working out what type of award certificate a player gets based on their average goal score. Enter the data below into the worksheet: Enter formulas to calculate the total goals scored for each player. Enter the functions to calculate the average, maximum and minimum goals for each player. Hint: Use the information in the tip box on page 8 of this task because you must check that the correct function arguments are being used in your functions. After entering correct formulas your worksheet should appear as: There are two types of award certificates that players can receive depending on their goal scoring average: If their average is 2 or under then they receive a merit certificate. If their average is above 2 then they receive an excellence certificate. Enter IF functions in an Award column to work out the type of certificate each player gets. Hint: Use??>2 in your IF function test replacing?? with a cells address. C:\Users\GerryKruyer\Documents\SPAN\ms-office\ms-excel\learning-tasks\level-2\task6\TYMSExcel6.docx Page 13

14 After entering correct formulas your worksheet should appear as: Save your worksheet with a suitable name. Validate your workbook. Oh dear, there are two input data errors in your worksheet: In Game 2 Cristina scored 6 goals. In Game 4 Lana did not score any goals at all. Alter your worksheet to reflect these two mistakes. Highlight all the cells in your spreadsheet. (Cells A1 to K13 should now be highlighted.) Click on the Home tab and then click on the Format button as shown on the right: Select AutoFit Column Width. Again save the worksheet and then back it up to your USB. Close your worksheet. Exit out of Excel. Have you backed up all of your work at the end of this lesson to your USB thumb drive? Have you been saving your work to the network drive every 10 minutes? Show your MS Excel documents to Mr Kruyer for assessment. Due Dates: All questions from this task and homework should be completed by next week s class. C:\Users\GerryKruyer\Documents\SPAN\ms-office\ms-excel\learning-tasks\level-2\task6\TYMSExcel6.docx Page 14