A macro is a "mini program" the user creates in Excel by actually going through the steps desired while Excel records the keystrokes and commands typed.
Explanation
####### appear if the cell is too narrow to display the numerical contents. To widen the column exactly enough to hold the longest entry in it: Double-click the divider between the column headers or choose Home→Cells→Format→AutoFit Column Width. To widen the column manually: Drag the divider between the column headers.
When entering formulas, you need to put an equals (=) sign in front. Otherwise, the formula will merely be text in a cell.
Profit is equal to Revenue(B1) - Expense(B2). There the formula in B3 should be =B1 - B2.
Headers and footers typically appear on every page of a report. In Excel 2010, a header is printed in the top margin, and a footer is printed in the bottom margin. Headers and footers are often used to identify the document and to display the page numbers. Unless you specify otherwise, Excel does not automatically add either a header or footer to a new workbook.
A pie chart would be meaningless with more than one data series, therefore Excel will not even produce a pie chart if you try to use more than one data series.