Simplify the following text for a Grade 6 native English-speaking person.
Original: The contestant in control was shown the first card in the row of five , the so-called `` base card , '' and could either keep it or replace it with the next card off the top of the deck , which they had to play . The contestant then guessed whether the next card in the row was higher or lower , and continued to do so as long as he or she guessed correctly .
Simplified: The contestant in control had to predict whether each card was higher or lower than the card before it .