One of the key issues is that formulas use cell references to do a calculation. As you can see below we used the AutoSum to calculate the numbers in A1,A2,A3 and A4 in the Calculations lesson.
Now this is a very powerful and easy way to do calculations but by writing the formula yourself you can do infinite calculations in infinite ways using columns and rows.
Double click the cell that you want the calculation to appear in (below is A6). Then by typing in the formula you see below into this cell and hitting the Enter key you will be adding the numbers in A1,A2,A3,A4 and the result will appear in A6.
Below you can see that you can also type the formula into the Formula Bar (fx). The formula will appear in both no matter which one you pick. You will notice when you hit the Enter key the figure will appear. To get the formula back you just double click that cell again.
Lets now use the same figures and get 1% of the total of all the numbers. Remember to double click the cell you want to work in. As you can see this is standard Maths to get 1%.
You could do =sum(A1+A2+A3+A4)/100 but using (A1:A4) is a short cut.
Below there are some headings that you can type in normally to give names to a column. Also notice you use a formula on any cells.
Below shows that you can use multiple formulas through out a spreadsheet. Use the AutoSum for the monthly totals.