I Have.Who Has.mental math card game focuses on base ten block representation for two-digit numbers. Each student gets a card. One student reads the 'I have' question and then the 'who has' question. The other players decided whether to respond after looking at their cards. The person who answers is the one whose 'I have' statement is the correct response. That person reads their 'I have' statement and then their 'who has' statement. Record the amount of time it takes to complete the activity and challenge the class to complete the activity even more quickly the next time! 36 cards. Grades 1-2.