Default size of number datatype

I would like to know what is the default size of number
datatype in Oracle  if the size is not specified while creating the table .

Create table emp
(empno number,
name varchar(20));

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davidgornshteinConnect With a Mentor Commented:

 If you are not defining restrictions on number
 size, you can insert every number within oracle
 internal definitons restrictions.

 It's from the oracle manual about system defined  

 The NUMBER datatype stores zero,
 positive, and negative fixed and
 floating-point numbers with magnitudes
 between 1.0 x 10 -130 and 9.9...9 x 10 125
 (38 nines followed by 88 zeroes)
 with 38 digits of precision.

 This means, that you can store every number.

 However, you should understand, that precision and
 scale in NUMBER(precision ,scale) is restrictions
 on number.

 Look at internal representation of number:

 Number defined in oracle as variable length sequence
 where first byte is exponent + sign (msb) and
 all other bytes are mantissa represented in excess 100
 and last byte is 0x66 for negatives.

  02 c1 33   - this means 2 -length, c1 - 128 - 65 =0
               0x33 = 51  
  (51 - 1) * 100^0 = 50


The default size is 38
Hi sumans1,
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Thanks for your help here, Dan.
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