Behavior of sequential circuits

[Nyasha]

Is there a systematic way in which l can determine the behavior of this sequential circuit ? The textbook gives me its counting sequence but l don`t understand how they came to it

 

[Quinzio]

What do you mean a systematic way ?

There's not a mathematical formula. That circuit has a clock so it's time dependent.
I think you know the behaviour of the Toggle flipflop, so it should be easy to understand why it counts.

 

[Nyasha]

Does it count from 0-7 then ?

 

[Quinzio]

Yes sure .