1. Graham invites 31 friends to his birthday party. He gives 5 balloons to each friend. How many balloons did he distribute?   2. There are 10 cakes. Each cake is cut into 7 pieces. How many pieces are there in all?   3. There are 16 sandwiches arranged in a tray. How many sandwiches are there in 9 trays?   4. Dad has planned 7 games for the party. Each game would have 8 winners. How many prizes would Dad give away?   5. There are 20 rows of tea cups. Each row has 10 cups. How many cups are there altogether?