The format of the cell that you are using isn't set
correctly. You will need to set the format to either
single or double. To learn more about it, go into a
table's design view, find a field with a data type of
number, and then put your cursor on format. Hit F1.
You'll get a list of the different data types you can
choose. Only some data types allow you to store
decimals. It'll tell you which ones.
