Who thought that the makkah of Hail )11,1) counted as 4 makkos?
At the end of the plague of Hail, the Torah states that not only did Pharaoh harden his heart, but even his servants hardened their hearts (9:34). The reason that even the servants hardened their heart now was that they had been told that HaShem was going to bring10 plagues upon Egypt. The mistakenly thought that the 7th plague counted as number 7-10 since it consisted of four elements: hail, fire, ear-splitting sounds (brought on from the storm-winds bringing the hail - Hakesav Vehakabalah, or from the smashing of the hail -stones on the ground - Netziv), and torrents of rain (9:33). Therefore, since in their minds the 10 plagues had already happened, they thought that they had nothing else to fear, and they therefore hardened their hearts (Tur).
