Calculate the error-prone format with recursive equation: 57-(25+ 18) 23+4×9.

Second, the basic knowledge

1. Merge two formulas into one.

Such as (1)18÷ 9 = 230-2 = 28 (2) 5× 9 = 4545+17 = 62.

2. The methods of finding multiples and multiples are confused.

For example, there are nine ducks, and the number of chickens is three times that of ducks. How many chickens are there?

There are nine ducks, three times as many as chickens. How many chickens are there?

3, counting, the composition of the number

For example, the two numbers adjacent to 600 are () and (); The two numbers adjacent to 398 are () and ().

The two numbers after 3299 are () and (); The two numbers before 2300 are () and ().

Five thousand and eight writing (); There are () hundreds of 3700; There are () tens in 4000.

4. It is often unexpected for students to find multiple relationships in the law.

Such as: 2, 4, 8,-; 2、6、9、 -

5. Division means error-prone.

For example, there are () 7s in 35, so () is () times that of ().

Third, the operation questions

1, symbols for drawing corners and forgetting to draw corners.

2, the number of leakage Angle

3. Draw the translated figure and count the squares.

4. Translation and rotation confusion

Translation is characterized by constant direction, and rotation is characterized by changing direction.

Fourth, solve the problem.

1. Buy the same pen. Xiaohong bought 5 pens and Xiaoming bought 8 pens. Xiaohong spends less 24 yuan than Xiaoming. How much is each pen?

There are nine red flowers in the flower bed, and the number of yellow flowers is three times that of red flowers. How many kinds of two flowers are there? How much more yellow flowers are there than red flowers?

3, science fiction books per 4 yuan, story books are three times less than science fiction books 1 yuan, how much is each story book?

Xiao Ming read a book with a page of 150. The first day, he read 40 pages. The next day, he read as many pages as the first day. How many pages are left?

Xiaoming has read 80 pages of books for three days, and there are 59 pages left.