500
Emma has 12 cards and Stan has 0. Stan takes some of Emma's cards. Then Emma has 9 cards. How many more cards does Emma have than Stan? Write the 2 equations that helped you solve the problem
12 - ____ = 9, so Stan took 3 cards. Stan has 3 and Emma has 9 now: 9 - 3 = 6, so Emma has 6 more cards than Stan.