numList:

First, ListRemove$($numList$,$ node $56)$ executes.

What node does node $67\text{'}$s prev pointer point to$?$

What node does node $67\text{'}$s next pointer point to$?$

Next, ListRemove$($numList$,$ node $51)$ executes.

What node does numList's head pointer point to$?$

What node does numList's tail pointer point to$?$