Microsoft Office Tutorials and References
In Depth Information
Calculating the quantities
Press Enter, the Tab key or one of the cursor keys and your formula will be entered
into the cell and the cursor will move to a different cell. Cell D5 will now show
the number 10, which is equal to the content of cell B1. The formula bar will show
you the formula you’ve entered into the cell to calculate that.
This isn’t the same as copying a cell with a number in it. If you copy a cell,
its contents are moved to another cell once only. If you use a formula in a
cell, its contents will be updated whenever related cells change.
Put the cursor on cell D5 and then click the formula bar. Because we’ll be
spending one night in the treehouse, the ﬁ gure we actually want for our hotel stay is one
less than the length of our total trip. To achieve that, we modify our formula so it
=B1 - 1
The spaces are optional, but including them can make it easier to read your
formula. To translate the formula into something resembling English, we want cell
D5 to be equal to the contents of cell B1, minus one. When you enter that
formula, the ﬁ gure in the cell for the booking at Hotel Pierre will change to 9.
It’s hard to justify letting off too many ﬁ reworks in celebration of that effect. But
try typing different numbers for the trip length into cell B1, and you’ll see that cell
D5 is immediately updated too. Imagine that you’ve got a spreadsheet that has 20
different values from spending money to beach hut rental, all of which depend on
the length of stay. You can update all of them simply by typing in a single number,
and see the effects ripple throughout the whole spreadsheet. This is what makes
Excel so powerful: you can describe the relationship between numbers, so that
Excel can recalculate things as circumstances change.
The best way to understand formulae is to try them out on screen and see
what happens when you make changes to the spreadsheet. You can always
Undo (CTRL+Z) if something unwanted happens.