1. There are 31 cakes. Each cake is cut into 9 parts. Each part is further cut into 3 pieces. How many cake pieces are there in all?   2. There are 5 balloons in a bag. There are 4 bags in one box. How many balloons are there in 23 boxes?   3. Everyday   Jimmy   exercises 28 minutes in the morning and 19 minutes in the evening. How many minutes does he exercise in 4 days?   4. A school has 5 dining halls. Each dining hall has28 tables. If there are four children to each table, how many children stay for lunch?   5. There are 6 paintings on each of three walls of a room. If an art gallery has 21 such rooms, how many paintings are there in its collection?