# 3 # Introduction Experience is the foundation of mathematics, problem is the core of mathematics, thinking is the core of mathematics, development is the goal of mathematics, and thinking method is the soul of mathematics. Mathematical thinking method is the essence of mathematical knowledge, the basic principle of analyzing and solving mathematical problems, the important connotation of mathematical literacy and the catalyst of cultivating students' good thinking quality. The following is the relevant information, I hope it will help you.

Tisch

Multiply multiple digits by one digit 1, estimate. (Find the approximate multiple digits first, and then calculate. Such as 497×7≈3500)

2.① Multiply 0 with any number to get 0;

② Multiply 1 by any number other than 0 to get the original number.

3. If there are several zeros at the end of the factor, add several zeros at the end of the product.

4. Three digits multiplied by one digit: the product may be three digits or four digits.

Formula: speed × time = number of people per car × number of cars = number of people in the whole car.

5. (About) Application:

(1) if there is "about" in the condition, but there is no "about" in the question, find the exact number. →(=)

(2) There are no conditions, but "about" appears in the question. Find out the approximate figure and use the estimate. →(≈)

(3) Conditions and problems are "about". Find approximate figures and use estimates. →(≈)

extreme

The score is 1. Divide an object or figure into several parts on average, and take a few of them, which is the score of the object or figure.

2. The more shares a whole is divided equally, the smaller the number each share represents.

3.① The numerator is the same, but the fraction with small denominator is large, and the fraction with large denominator is small.

(2) The denominator is the same, the numerator is large, and the numerator is small.

4.① Addition and subtraction of fractions with the same denominator: the denominator is unchanged, only the numerator is added and subtracted.

② Fractions minus 1: 1 can be regarded as fractions with the same numerator and denominator.

Tisso

A quadrilateral 1, a closed figure with four straight sides and four corners, is called a quadrilateral.

2. Features of quadrilateral: It has four straight sides and four corners.

3. Features of rectangles: Rectangles have two lengths, two widths, four right angles and equal opposite sides.

4. Characteristics of a square: it has four right angles and four equal sides.

5. Rectangular and square are special parallelograms.

6, the characteristics of parallelogram:

(1) The opposite sides are equal and the diagonal lines are equal.

② Parallelogram is easy to deform. (Triangle is not easy to deform)

7. The length of a closed graph is its perimeter.

8. Formula. The perimeter of a rectangle = (length+width) ×2 The perimeter of a square = side length ×4.