1. There are fixed point and floating point numbers.
2. A fixed point number is described by the number of significant digits and the scale. The maximum number of significant digits is 18.
3. A floating point number consists of a mantissa and an exponent. The mantissa may have up to 18 significant digits. The valid range of values for floating point numbers consists of the intervals from -9.99999999999999999E+62 to -1E-64 and from +1E-64 to +9.99999999999999999E+62 and the value 0.0.
4. All numbers can be compared to each other.