CS102, Fall 2000, Day 3, Tuesday,October 24

• Range:  You specify a range by "thumbtacking" a beginning and end cell.  B4:B7 is cells B4,B5,B6,B7.  A range is always rectangular (later we'll see how to choose more than one rectangle at a time). 
  To specify a rectangle which is more than one row high and also more than one column thick, choose any two diagonal corners.   The rectangle on page 1.19 is given by range F8:H16, the top left and bottom right corners.  You could have used F16:H8 instead; the top right and bottom left (Excel will rename it to use the top left/bottom right).

• Absolute and relative addressing.  ( Make a note of F4 key (p.2.14), that info is hard to find. You can type in the $ if you lose it.)
• Absolute is like giving map coordinates (longitude/latitude).
• Relative is like giving driving instructions from here to there (go two blocks north, turn left, go three blocks.)
• Inserting rows:  Mostly Excel will adjust formulas.  One exception:  If you insert a row at the end or beginning of a range (for instance that you are taking a sum or average of), it won't get inside the "thumbtacks."  Result?  Your info won't go into your sum or average.  A very common and insidious mistake.
• Testing: Mostly Excel figures out what you have in mind when you make changes, but always check on your formulas, when you create them, then especially after moving, inserting rows or cells! p.2.22 gives good strategies. I like using simple numbers.
• Pointing to build formulas: (p.2.21) The text uses this method to get a range.  You can use it effectively in any formula, and it was one of the fundamental features of the first spreadsheet program. You don't need to know the reference label of  a cell, you just need to be able to find it!
  For example, to create (A1 + A2)/2 (the average of A1 and A2) in cell A4:
• Make cell A4 the active cell, type  = , then type  (  
• Click with the mouse in the cell of your formula.  The moving dotted border tells you you can point.
• Move the cursor to A1 (you can use arrow keys or the mouse). As you move, the cell you are over will appear in your formula.
• When you have the correct cell in the formula, type the next thing in the formula.  Type  +
• Move the cursor to the next cell (A2), and when it is correctly pasted in the formula, type the next things, 
  here   )/2
• Hit Enter when the formula is complete.
• (If  a formula that you're making is suddenly full of garbage, you may have gotten into pointing mode by mistake.)

• You'll go into a lot of new dialog boxes.  If you're on top of this stuff, look around and see what else you can do there. (E.g. p. 3.14, Format Cells box:  You can make the text go up-and-down, or sideways. Try it out.)
• Color:  Effective for on-screen display, but that's not your usual use of a spreadsheet. 
• If your Print Preview shows colors rather than gray, and you've got a black-and-white printer (or plan to photocopy your result), you may not get what you want when the color translates to a gray.
• Moral: Think about the printed result. Use gray shades instead of colors if you can't print color.

File:Page Setup...Sheet gives a "Black and White" printing option, which will eliminate color and gray shades entirely.