Answer:
The equation you would use is 21 ÷3.
Explanation:
You would use that equation because you use 3 tickets per game and you used 21 so then you would have played 7 game in total I know this because you can use multiplication which is 7x3=21 or you could do 7+7+7=21.You would use the equation 21 ÷3 and you would play 7 games in total. Hope it helps you.