how many jobs need to be created to break even?

Normally about 225,000. However, we currently have a large backlog of people who gave up looking for work but will presumably return once jobs become more available. There's also a large number of illegal immigrants to whom Obama is now giving work permits.

With a population growth of 1%, 250,000 more jobs needed each month.

125k-150k jobs a month to sustain...more to break the trend.