12- 15× 25 = 20 yuan.
A: 20 yuan.
2. Each juvenile newspaper is 0.80 yuan, and five classes (1) students subscribe to 15 copies. If the money is just enough to subscribe to 24 math newspapers, how much is each journal?
0.8× 15 ÷ 24 = 0.5 yuan.
A: Every periodical is 0.5 yuan.
There is a batch of paper that can bind 24 pages of exercise books of 2 16 each. If you want to bind each 18 page exercise book, how many copies can you bind?
2 16× 24 ÷ 18 = 288 copies.
A: You can bind 288 copies.
4. Bind exercise books. It takes 4800 pages to bind 200 books. If there are 12000 pages, how many such exercise books can be bound?
4800 ÷ 200× 12000 = 288000 copies
A: It can bind 288,000 volumes.
A square brick needs 500 yuan to build an office of 80 square meters. How many floors does a 120 square meter classroom need?
500 ÷ 80× 120 = 750 yuan
A: 750 yuan, please.