When you create a new workbook the default number of worksheets is 3. It is just the automatic number created. If you don't want it to do this you can change the default number created in future.
Click on the help icon and type in "change default number of worksheets" and read the article for more information.
You will learn how to make models, shortcuts and other various excel functions that are not obvious. They are great for someone who uses excel all the time.
The same exact reasons you'd use sheets in the first place. The camo pattern is just a color/pattern choice. Nobody in a tactical environment is going to have a tactical bed which they put camoflage sheets on.
I did. Once.
Excel 2013 uses a .xlsx extension.
excel
Diary-keeping, letter writing, company accounts, payroll, time-sheets...
MS Excel uses two types of data: text and numbers.
Israel uses the same system of measuring time that the rest of the world uses.
Colorado uses mountain time and Oklahoma is central time.
The standard extension for Excel workbooks is xls for versions up to 2003. Excel 2007 uses xlsx as its extension for workbooks.
it is not for any one to use
Cascading Style Sheets (CSS) uses classes.