What is not holding? and what are you trying to do when you right click on a cell?
Are you able to type formulas in the cells?
Ok to set the cells to show 1-5 for 1/5/2010, select that cell then go to Format > Cells, then click Custom from the Category list on the left pane, then type the following in the field on the right:
then click OK.
Now type a full date in that cell, i.e. 1/5/2010 and you will see the cell displaying 1-5
Try that and let me know so we can go to the next part of the question
Now with regard to the decimals,select the cells or columns that you want to format without decimals, then go to Format > Cells, then click Number from the Category list on the left pane, then type 0 in the 'Decimal places' field on the right. Click OK
Let me know if you still need help with this