A math problem is about Xiao Ming's reading Xiao Ming read a book. On the first day, he read 3 / 8 of the whole book. On the second day, he read the remaining 1 / 3. On the third day, he read the remaining 1 / 5. Finally, he left 20 pages to read. How many pages are there in this book?

If you read 3 / 8 on the first day, you will have 5 / 8 left. If you read 5 / 8 * 1 / 3 = 5 / 24 on the second day, you will have 1-3 / 8-5 / 24 = 5 / 12. If you read 5 / 12 * 1 / 5 = 1 / 12 on the third day, you will have 4 / 12 left, that is, 1 / 3. So the total number of pages is 20 / (1 / 3) = 60!

If a natural number is a multiple of 3 and 4, and there are 10 divisors including 1 and itself, then the natural number is______ ．

According to a natural number is a multiple of 3 and 4 can be obtained: the natural number is a multiple of 12, 12 multiples are: 12, 24, 36, 48, 60 12 = 22 × 3, so its divisors are: (2 + 1) × (1 + 1) = 6; 24 = 23 × 3, so its divisors are: (3 + 1) × (1 + 1) = 8; 36 = 22 × 32

The following is the students played the stone scissors cloth, now we agreed: cloth win stone 9 points, stone win Scissors 5 points, scissors win cloth 2 points
In the process of playing this game, Xiaokang won 31 times and scored 162 points, of which scissors won cloth 11 times. Smart students, can you work out how many times Xiaokang cloth won stone and stone won scissors

Set up a system of equations, cloth wins stone x, stone wins scissors y. x + y = 20, 9x + 5Y = 140
x=10,y=10

Use a 20 cm long and 15 cm wide rectangular sheet iron to make a 5 cm deep rectangular sheet iron box without cover (excluding the thickness of welding joint and sheet iron). What is the maximum volume of this sheet iron box?

As shown in the figure, the volume of the tin box: 5 × (20-5 × 2) × (15-5 × 2), = 5 × (20-10) × (15-10), = 5 × 10 × 5, = 250 (cm3). Answer: the maximum volume of the tin box is 250 cubic centimeters

Set the table and chair in the following way. One table can seat 4 people, and two tables can seat 6 people. How many people do you need to sit 80 people?

1. The question should be how many tables for 80 people? If you ask how many people, 80 people have been answered
2. Tables are placed side by side, so there are 4 people in one table, 6 people in two, 8 people in three, 10 people in four, and so on
3. The rule is number = number of chairs = number of tables * 2 + 2, so it takes 39 tables for 80 people

3 / 10 sq m = () sq cm

3000

Mr. Zhang wants to buy 46 story books. How much does it cost? A story book costs 8.7 yuan

46×8.7＝400.2

1 8 27 () find the law
yes
fifty-eight
thirty-six
forty-five
seventy-two
These are the options

1 8 27 ( 58 )
The rule is: 1 1 + 1 * 9-2 + 3 * 0 = 8 8 + 2 * 9-2 + 3 * 1 = 27 + 3 * 9-2 + 3 * 2 = 58

The unit of measurement of time based on movement is called the month

Cycle of lunar phase change

What did the poet of Bai Hua praise by Bai Hua?

A man like a birch

A math problem is about Xiao Ming's reading Xiao Ming read a book. On the first day, he read 3 / 8 of the whole book. On the second day, he read the remaining 1 / 3. On the third day, he read the remaining 1 / 5. Finally, he left 20 pages to read. How many pages are there in this book?