Calling the radio station

I rang the radio station and got straight through to the DJ, he told me that as i was the first caller through he would ask me a question and if i answered correctly id win the star prize…great i answered…”The question is on maths” he said…”brilliant i have a degree in maths and teach it at our local school” i replied, so he said “for two tickets to Justin Beibers next concert and back stage passes to meet him and spend the evening…what is 2+2″……7 i replied…….