Numbers can be written as integers, decimal numbers, dates, times, or datetime values. They can also be included in scientific notations with an E preceding the power of ten. For example, these are all numbers:
. 1 12 1.234 3E3 0.314159265E+1 1E-20 01JAN98
Note: A single period by itself is considered a missing numeric value (sometimes called NaN for “not a number”).
For more information about dates, times, and date-time values, see Date-Time Functions and Formats in the Types of Data. See Currency in the Types of Data for more information about combining numbers with currency symbols.