This is fun! It’s easier to remember and use than any of the methods listed on Wikipedia: https://t.co/VP6xlrfmpa

10a + b = 0 (mod 7)
⇒ 3a + b = 0 (mod 7)
⇒ 3a + 15b = 0 (mod 7)
⇒ a + 5b = 0 (mod 7) https://t.co/uPsrwgO8VH

— .robin. (@robinhouston) November 14, 2019