How to make a very old computer work out what 6 times 9 plus 11 is

 The plan

     Hold the number 6 in your CPU, as X
     Hold the number 9 in your CPU, as Y
     Multiply X by Y
     Replace Y with 11
     Add Y to X
     Show X on the lights on the front panel
     Stop

 The Manual

     HALT               Stop
     SETX  N            X set to N
     SETY  N            Y set to N
     LOADX N            X set to memory[N]
     LOADY N            Y set to memory[N]
     INX                accept X from switches
     INY                accept Y from switches
     OUTX               display X
     OUTY               display Y
     ADDX               X set to X + Y
     ADDY               Y set to X + Y
     SUBX               X set to X - Y
     SUBY               Y set to X - Y
     MULX               X set to X x Y
     MULY               Y set to X x Y
     DIVX               X set to X / Y
     DIVY               Y set to X / Y
     and so on

 Encode it

     Hold the number 6 in your CPU, as X     -> SETX  6
     Hold the number 9 in your CPU, as Y     -> SETY  9
     Multiply X by Y                         -> MULX
     Replace Y with 11                       -> SETY  11
     Add Y to X                              -> ADDX
     Show X on the lights on the front panel -> OUTX
     Stop                                    -> HALT

 Now type that into the computer and let it do the translation itself