MAT C=A*B 90 MAT D=INV(C) 100 MAT PRINT D, The output would be 2 2 1 1 -1 0 4 -3 -2 Debugging SOBS had primitive debugging capabilities, limited mostly to the TRACE statement. TRACE ON would cause the interpreter to print each line number as it was executed. References BASIC interpreters ICL programming languages Science and technology in Hampshire University of Southampton BASIC programming language family