Purpose Used for any numeric value, including fractions and numbers of high decimal precision. This data type is less efficient than the Integer and Long data types, but more flexible. The Single data type has the same constraints and size limits as Double. You can use these data types interchangeably. FCAS treats the traditionally smaller Single data type as a Double to support legacy BASIC code. Acceptable values -1.79769313486231E308 to  1.79769313486231E308