123456 => 123456 # Fixnum
0d123456 => 123456 # Fixnum
123_456 => 123456 # Fixnum - underscore ignored
-543 => -543 # Fixnum - negative number
0xaabb => 43707 # Fixnum - hexadecimal
0377 => 255 # Fixnum - octal
-0b10_1010 => -42 # Fixnum - binary (negated)
123_456_789_123_456_789 => 123456789123456789 # Bignum