Need help with page replacement algorithm methods.

I dont know how to do working set method. delta is 3

allocated 3 page frames in main memory 1 2 3 4 2 1 51 2 4 4352 12 1 For the three page replacement algorithms shown below, complete the table to indicate which pages are in main memory after each reference. For working set, as- sume Delta is 3. (Be careful! Your first mistake in a column may cause all succeeding answers to be wrong.) Reference Memory Contents - LRU OPT working set