gistfile1.txt

Fixnum

Holds Integer values that can be represented in a native machine word (minus 1 bit).
If any operation on a Fixnum exceeds this range, the value is automatically converted to a Bignum.

pry.rb

[1] pry(main)> 10.class
=> Fixnum
[2] pry(main)> 10.is_a?(Integer)
=> true
[3] pry(main)> 10.is_a?(Fixnum)
=> true
[4] pry(main)> 10.is_a?(Bignum)
=> false

[5] pry(main)> 999999999999999999999999999999.class
=> Bignum
[6] pry(main)> 999999999999999999999999999999.is_a?(Integer)
=> true
[7] pry(main)> 999999999999999999999999999999.is_a?(Fixnum)
=> false
[8] pry(main)> 999999999999999999999999999999.is_a?(Bignum)
=> true