The number is this:
There's no need to guess when we have documentation for BigDecimal#inspect!
Returns debugging information about the value as a string of comma-separated values in angle brackets with a leading #:
BigDecimal.new("1234.5678").inspect #=> "#<BigDecimal:b7ea1130,'0.12345678E4',8(12)>"
The first part is the address, the second is the value as a string, and the final part ss(mm) is the current number of significant digits and the maximum number of significant digits, respectively.