Very pertinent at this juncture of the year, to the Hagoddoh:- Rabbi Eliezer holding each plague to be 4, V Rabbi Akiva holding each plague to be 5.
Rabbi Eliezer’s 4 is based on Middas hoRachamim, since YudKehVovKeh is spelled with 4 letters.
Rabbi Akiva’s 5 is based on Middas haDin, since Elokim is spelled with 5 letters.