四則運算 (多位數) ：練習題

A machine in a factory produces \( 420 \) parts every hour. It runs for \( 8 \) hours. If \( 1560 \) parts are found to be defective and are discarded, how many good parts are left?

A factory produced $$1500$$ toy cars in January. In February, they produced $$1/3$$ more than in January. In March, they produced $$200$$ fewer toy cars than in February. How many toy cars were produced in total over the three months?

A baker made $$240$$ cookies. He put $$6$$ cookies in each small box and sold $$25$$ small boxes. He then put the remaining cookies into large boxes, with $$10$$ cookies in each large box. How many large boxes did he fill?

A theater has \( 24 \) rows of seats, with \( 50 \) seats in each row. For a certain show, \( 850 \) tickets were sold in advance. Later, \( 15 \) groups of \( 12 \) people each arrived and bought tickets at the door. How many seats are still empty?

A library received a shipment of \( 840 \) new books. These books are placed on shelves that hold \( 24 \) books each. If there were already \( 55 \) full shelves of books in the library, how many full shelves are there in total now?

A stadium has 15,000 seats. If there are 75 rows with an equal number of seats in each row, how many seats are in each row?

A baker made $$ 576 $$ cookies. He packed them into boxes, with each box holding $$ 18 $$ cookies. If he sold $$ 25 $$ boxes, how many cookies are left?

A farmer produces 15,600 liters of milk. He fills 450 containers that hold 25 liters each. The remaining milk is put into 10-liter jugs. How many 10-liter jugs does he need?

A school collected $$285$$ old books in the first week and $$367$$ old books in the second week. Then, they donated $$150$$ books to a local orphanage. How many books does the school have left?

A cinema has $$35$$ rows of seats. Each row has $$28$$ seats. For a special event, they added $$120$$ extra seats. If tickets were sold to $$1050$$ people, how many seats remained empty?