This is an online calculator for logic formulas. It can evaluate predicates and formulas given in the B notation. Under the hood, we use the ProB animator and model checker. The above calculator has a time-out of 2.5 seconds, and MAXINT is set to 127 and MININT to -128. An alternative version of the calculator is available at the Formal Mind website. You can also download ProB for execution on your computer, along with support for B, Event-B, CSP-M, TLA+, and Z. There are also 64-bit versions available for Linux and Mac (the above calculator only uses the 32-bit version).
If you face any problem please submit a report to our bug tracking system.