Create a state diagram for a system that that given up to $4$ bit $($positive$)$ number will sum the value of that number and each lower value. For example a $3$ would return $3+2+1+0=6.$ Pay attention to how big numbers are so they do not overflow where you store them. This is likely made from a counter, an adder $($more than $4$ bits$),$ and some extra storage registers.