80 ÷ 36 …… 余836 ÷ 8 ……余48÷ 4 ……余0即最大公约数为480 - 36 = 4444 - 36 = 836 - 8 = 2828 - 8 = 2020 - 8 = 1212 - 8 = 48 - 4 = 4OK是4