You can find the payoff or net profit of a combination of option positions by merely adding the payoffs or net profits of the individual option positions.

A straddle is a position that is long both a call and a put with the same strike price. Consider such a position with a strike price of $50. The premium for the call is $3 and the premium for the put is $2. Create a table and graph the overall payoff and net profit of this position as function of ST, the stock price at maturity. Vary ST from $40 to $60 in increments of $2.