Write down the three major points of numbers and algebra, graphics and geometry, statistics and probability 1. Write the content and knowledge points of the lecture 2. Give examples 3. Understand the

Write down the three major points of numbers and algebra, graphics and geometry, statistics and probability 1. Write the content and knowledge points of the lecture 2. Give examples 3. Understand the situation. Bye

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Compilation of number and algebra knowledge

Anonymous | 2012-06-13 | Share

About the 6th grade final review At least 10 points of sorting out part of "Numbers and Algebra", urgent!

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Number and algebra knowledge points

Formulas related to numbers: 1. Divisor ÷ divisor = quotient 2, multiplier × multiplier = product 3, minuend - minuend = difference 4, addend + addend = sum

Knowledge point 1: Integers

1. The range of integers

Integers include natural numbers and negative integers, or integers are composed of positive integers, zero, and negative integers.

(1) Natural numbers

The meaning of natural numbers: When we count objects, they are used to express the number of objects 0,1,2,3,4,5,…. .called natural numbers. The number of natural numbers is infinite, and there is no largest natural number.

The meaning of "0": "0" means there is no object at all. It plays a placeholder role in counting, indicating that there is no counting unit at this digit. "0" can also represent the starting point, dividing point, etc. "0" is the smallest natural number.

(2) Positive numbers

The definition of positive numbers. The numbers 8, 16, 200 that we have learned before are called positive numbers.

How to write and read positive numbers. Positive numbers can also be preceded by a "+" sign. For example: +8 is read as: positive eight. The "+" sign can generally be omitted.

(3) Negative numbers

Definition of negative numbers Numbers like -1, -5, -132... are called negative numbers. "One" is called the negative sign.

How to write and read negative numbers. Add a "one" sign in front of a negative number. For example: -15 is read as: minus fifteen. The larger the number, the smaller the negative number.

"0" is neither a positive number nor a negative number.

(4) The connection and difference between integers and natural numbers

Natural numbers are all integers, but not all integers are natural numbers, including negative integers.

Knowledge point 2: Percent

1. The meaning of percentage

(1) A fraction with a denominator of 100 is called a percentage.

(2) A number that expresses what percent of another number is called a percentage. Percentage is also called percentage or percentage.

Summary of knowledge points for percentage application questions:

1. Find common percentages such as: compliance rate, passing rate, survival rate, germination rate, attendance rate, etc.

To find a percentage is to find out how many percent one number is of another number

2. To find out how many percent more (or less) one number is than another number in real life , people often use percentage increase, percentage reduction, percentage saving, etc. to express the extent of increase or decrease.

Find how many percent more A than B (A-B)÷B

Find how many percent less B than A (A-B)÷A

3. Find what percent of a number is a number (unit "1") × percentage

4. If you know what percent of a number is, find the part of this number Amount ÷ percentage = a number (unit "1")

5. The discount is a few tenths, which is also a few tens of percent.

6. Interest rate The money deposited in the bank is called principal.

The extra money paid by the bank when withdrawing money is called interest.

The ratio of interest to principal is called the interest rate.

Interest = principal × interest rate × time

Percents are usually not written as fractions, but are represented by the symbol "%", which is called the percent sign.

Knowledge point 2: Decimals

1. The meaning of decimals

Divide the integer "1" equally into 10 parts, 100 parts, 1000 parts... like this 1 part or several parts is a few tenths, a few hundredths, a few thousandths... It can be expressed by decimals. One decimal place represents tenths, two decimal places represent hundredths, and three decimal places represent thousandths...

2. Comparison of decimal sizes

Compare two For the size of decimals, first look at their integer parts. The number with the larger integer part is larger; if the integer parts are the same, the number with the larger tenth place is the number; if the number with the tenth place is also the same, the percentile is The number above is larger...

3. Rewriting of numbers and finding approximate numbers

Rewriting of numbers and omitting the mantissa after a certain digit of the number is written as an approximate number Method

For the convenience of reading and writing, larger numbers are often abbreviated as numbers using "ten thousand" or "hundred million" as the unit. For example: 2365500 = 2365500 (rewrite the number using "ten thousand" as the unit). Sometimes you can omit a certain mantissa of the number and write it as an approximate number as needed. For example: 2365500≈2.37 million (omitting the mantissa after the ten thousand digit). Sometimes it is also required to keep an approximate number with one decimal place. For example: 7.62983≈7.6 (retain one decimal place).

When obtaining approximate numbers, the "rounding method" or "rounding method" or "tail-off method" is often used to omit the mantissa after a certain digit of a number.

Knowledge point three: Fractions

1. The meaning of fractions is to divide the unit "1" into several equal parts, which means... Expand all>

873287463 | 2012-06-13

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