Tough Number Riddle: Guess ?? in 16, 06, 68, 88, ??, 98

Look at the series of numbers given in the riddle and find the connection between them. Find value of ?? in the following sequence. 16, 06, 68, 88, ??, 98 So were you able to solve the riddle? Leave your answers in the comment section below. You can check if your answer is correct by