Narrated Umar bin Al-Khattab: I heard Hisham bin Hakim reciting Surat Al-Furqan during the lifetime of Allah's Apostle and I listened to his recitation and noticed that he recited in several different ways which Allah's Apostle had not taught me. I was about to jump over him during his prayer, but I controlled my temper and when he had completed his prayer, I put his upper garment around his neck and seized him by it and said, "Who taught you this Surat which I heard you reciting ?" He replied, "Allah's Apostle taught it to me". I said, "You have told a lie, for Allah's Apostle taught it to me in a different way from yours". So I dragged him to Allah's Apostle and said, "I heard this person reciting Surat Al-Furqan in a way which you haven't taught me!" On that Allah's Apostle said, "Release him (Umar) recite, O Hisham!" Then he recited in the same way I heard him reciting. Then Allah's Apostle said, "It was revealed in this way", and added, "Recite, O Umar", I recited it as he had taught me. Allah's Apostle then said, "It was revealed in this way. This Qur'an has been revealed to be recited in seven different ways, so recite of it whichever is easier for you." (Sahih al-Bukhari: vol. 6, bk. 61, no. 514)

I am very confused by that. How can there be different ways to recite the Quran? What exactly is going on in this hadith? are there some people that were taught completely different meanings and versions or what exactly is it that is going on that is causing confusion between the different people in this hadith