if you subtract two delayed unit step functions, is the resultant a unit step function too? what is the value at the last point? 0 or 1? similarly, if you add 2 unit step functions will the magnitude of the resultant funtion be 1 or 2?
Just draw them out and do the additions and subtractions that way. The step function is rather simple so a quick pictoral representation should show you your answer.
i still dont get it. could u just tell me that when u subtract 2 unit step functions, will there or will there not be a discontinuity at the last point?