Unit 1 (location):

In order to determine the position of a point, two data are needed.

To represent the position of an object with a number pair, you must first determine the column, and then determine the row.

Unit 2 (Fractional Multiplication):

The significance of fractional multiplication is the same as that of integer multiplication, which is a simple operation to find the sum of several identical addends.

The calculation rule of fractional multiplication by integer: fractional multiplication by integer, the product of fractional numerator and integer is numerator, and the denominator remains unchanged.

Fraction multiplied by fraction: Fraction multiplied by fraction should be numerator multiplied by numerator and denominator multiplied by denominator. What can be divided can be divided first and then multiplied.

The order of fractional mixing operation is the same as that of integer operation. From left to right, multiply first, then divide, then add and subtract. If there are brackets, count them first.

The commutative law, associative law and distribution rate of integer multiplication are also applicable to fractional multiplication.

Two numbers whose product is 1 are reciprocal.

To find the reciprocal of a fraction (except 0), just exchange the numerator and denominator of this fraction.

To find the reciprocal of an integer (except 0), you only need to divide the integer into fractions with the letter 1 and exchange the positions of the numerator and denominator.

Unit 3 (Fractional Division):

Dividing a number by a number that is not equal to 0 is equal to multiplying the reciprocal of this number.

The divisor is greater than 1 and the quotient is less than the dividend; The divisor is less than 1 (less than 0) and the quotient is greater than the dividend.

Division of two numbers is also called the ratio of two numbers.

In the ratio of two numbers, the number before the ratio sign is called the first term of the ratio, and the number after the ratio sign is called the last term of the ratio (the last term of the ratio cannot be 0). The quotient obtained by dividing the former term by the latter term is called the ratio.

The two items before and after the ratio are multiplied or divided by the same number at the same time (except 0), and the ratio remains unchanged. This is the basic nature of the so-called ratio.

Unit 4 (Circle):

The point where all creases intersect at the center of the circle is called the center of the circle, generally represented by the letter O, the line segment connecting the center of the circle with any point on the circle is called the radius, generally represented by the letter R, and the line segment passing through the center of the circle with both ends on the circle is called the diameter, generally represented by the letter D..

In the same circle, there are countless radii and diameters. The length of the diameter is twice that of the radius, and the length of the radius is 1/2 of the diameter. d=2r r=d/2

The center of the circle determines the position of the circle, and the radius determines the size of the circle.

A circle is an axisymmetric figure with numerous axes of symmetry. A straight line with a diameter is the symmetry axis of a circle.

The diameter of the line segment with two ends on the circle is the largest. The diameter is longer than any string.

The length of the curve forming a circle is called the circumference. The circumference and diameter of any circle are fixed numbers. We call it pi, which is represented by the letter ∏ (circumference/diameter = ∏). It is an infinite acyclic decimal, and generally only its approximate value is taken in practical application, that is, ∈≈3. 14. C=∏d or C=2∏r

Divide the circle into several parts equally. The more divided parts, the closer the figure is to the rectangle. The length of a rectangle is half of a circle, which is denoted as ∏r, and the width is the radius of a circle, which is denoted as r, because the area of a rectangle = length× width, and the area of a circle =∏r×r=∏r square.

S ring =(R square -r square) ∈

The circumference is equal, the area of the circle is the largest and the area is equal. Circle c is the shortest.

Gap between starting lines of adjacent runways = runway width × 2× ∏ = 2×× (r-r)

Unit 5 (percentage):

Percent indicates the percentage of one number to another. Percentages are also called percentages or percentages.

To convert decimals into percentages, just move the decimal point two places to the right and add hundreds of semicolons at the end. To convert percentages to decimals, simply remove the percent sign and move the decimal point two places to the right.

The percentage is divided into several parts. First, rewrite the percentage into a fraction with the mother letter 100, and convert it into the simplest fraction if it can be simplified.

When a fraction is converted into a percentage, it is generally converted into a decimal (three decimal places are generally reserved when it is used up) and then converted into a percentage.

A few percent discount means a few tenths, that is, dozens of percent.

The tax paid is called tax payable, and the proportion of tax payable to various incomes is called tax rate. The money deposited in the bank is called the principal; The extra money paid by the bank when withdrawing money is called interest; The ratio of interest to principal is called interest rate.

Unit 6 (Statistics)

Histogram can represent quantity, and line chart can represent growth and change. The fan-shaped statistical chart can clearly understand the relationship between the number of each part and the total.

separate

bonus

Division symbol (÷)

divisor

business

mark

molecule

Fraction line (-)

denominator

Fractional value

compare

ancestors

Scale mark (:)

What followed.

specific value

1/2=0.5=50% 1/3=0.3≈0.33≈33.3% 2/3=0.6≈0.33≈33.3%

1/4=0.25=25% 3/4=0.75=75% 1/5=0.2=20% 2/5=0.4=40% 3/5=0.6=60% 4/5=0.8=80% 1/8=0. 125= 12.5% 3/ 8=0.375=37.5% 5/8=0.625=62.5% 7/8=0.875=87.5% 1/20=0.05=5%

1/25=0.04=4% 1/50=0.02=2% 1/ 100=0.0 1= 1%

1∏=3. 14 2∏=6.28 3∏=9.42 4∏= 12.56 5∏= 15.7 6∏= 18.84 7∏=2 1.98 8∏= 15. 12 9∏=28.26 1 0∏=3 1.4 16∏=50.24 25∏=78.5 36∏= 1 13.04 49∏= 153.86 64∏=200.96 8 1∏=254.34