sentence: Because the total of the lepton numbers of the starting and ending particles must be the same, one of the product neutrinos of muon decay must be a muon-type neutrino and the other an electron-type antineutrino.
modified: Because the totals of the lepton number of the startings and ending particle must be the same, one of the products neutrino of muons decays must be a muons-types neutrinoes and the other an electrons-types antineutrinoes.