Primary math problems are limited to three questions per day

One question: Set the actual daily repair x meters, according to the meaning of the topic.

10-2) x = 12 times 10

x=15A: 15 meters per day.

Question 2: Set x hours can be bound completely, according to the meaning of the topic.

180 times 10 = (180 + 20) x

x=9A: It can be bound in 9 hours.

Three questions: The stamp album has x pages, according to the title.

300 divided by 15 = 168 divided by (x) - 8

x=6A: The album has 6 pages.

1. 12 * 10 = 120 (m) 120 divided by (10-2) = 15 (m) Answer: Actually repair 15 meters per day.

2. 180 * 10 = 1800 (book) 1800 divided by (180 + 20) = 9 (hours).

A: It can be booked in 9 hours.

3. 300 divided by 15 = 20 (sheets).

168 divided by (20-8) = 14 (pages).

A: Dongdong's philatelic album has 14 pages.

12*10 (10-2) = 15 days.

180*10 (180+20)=9 hours.

Xiaohua per page: 300 15 = 20 sheets.

Knock knock per page: 20-8=12 sheets.

Total 168 12=14 pages.

1: 12*10 (10 2) 15 meters.

2: 180*10 (180+20) 9 hours.

Three: 168 (300 15-8) 14 sheets.

Multiply and divide.

120 divided by (10-2) = 15

1800 divided by (180+20) = 9 hours.

300 divided by 15-8 = 12

168 divided by 12 = 14 pages.

The plan is: the teacher takes one student to the station first, the teacher walks at the same time, the other student walks forward at the same time, and the teacher sends the first student to the station and immediately turns back to pick up the second student and then goes to the station.

First of all, change the way the speed is expressed: the speed of the car is 45 kilometers per hour, which is actually 45 60 = 3 4 kilometers per minute; The speed of walking is 5 kilometers per hour, actually.

5 60 = 1 12 km min.

1. It takes 15 (3 4) = 20 minutes for the teacher to send the first student to the station.

2. In these 20 minutes, the second student walked 20*(1 12)=5 3 kilometers, and the distance between the second student and the station was 15-(5 3) kilometers, and the teacher set off from the station to pick up the second student, and the second student was also walking, and it took [15-(5 3)] [(3 4)+(1 12)] for the teacher to turn back and pick up the second student

16 minutes. 3. It took 16 minutes for the teacher to pick up the second student from the station, 16*(3 4)=12 kilometers, that is, the teacher picked up the second student 12 kilometers away from the station.

At this time, it takes 12 (3 4) = 16 minutes to get to the station.

4. The shared time is 20 + 16 + 16 = 52 minutes. All arrived at the station in 55 minutes.

Send a student first.

The time it takes to get to the station is 15 45 = 1 3

Students are sent while walking.

So walked 5*1 3=5 3 km.

The teacher drove back to meet the students.

The time required is (15-5 3) (45+5)=4 15, at which point the student walks another 5*4 15=4 3 km.

The rest of the distance is (15-5 3-4 3) = 12 and the remaining time is 12 45 = 4 15

The total time is (1 3 + 4 15 + 4 915) * 60 = 52

The teacher takes one student with him, the other student walks on the road, and then the teacher comes back to pick up the teacher who took the one and asks for it, 15 45 = 1 3

Hours students are gone.

5*(1 3)=5 3 km.

The teacher came back to pick him up, and he met the need to go.

Hours to bring again.

To the school needed.

hours so the minimum required.

Hours are 52 minutes.