Explanation :
Take one stick from right-hand side 77 and one stick from middle 77 and create a + sign in between the middle 77, which becomes 7+1 the correct equation we get is 77 - 7 + 1 = 71.
Matchstick Image : Show Answer Matchstick Puzzles 77-77=77
Matchstick Image : Answer Matchstick Puzzles 77-77=77