The first unit of the first volume of the fourth grade of Mathematics published by People's Education Press focuses on "understanding large numbers", teaching students to know more than 100 million numbers simply, and to know and learn to use calculators and abacus.
An overview of the mind map of "understanding large numbers"
Synthesis of 1. 1.
1. 1. 1. Counting unit
1. 1. 1. 1.
1.1.1.1.The measured size.
1. 1. 1.2. Definition
1.1.1.2.1.The propulsion rate between two adjacent counting units is 10.
1. 1. 1.3. One, ten, hundred, thousand, ten million, ten million, one billion, one billion, one billion, one billion, one billion.
1. 1.2. Numeric
1. 1.2. 1.
1.1.2.1.1.The position occupied by each number is called a number.
1. 1.2.2. Starting from the unit, every four digits are one level, followed by: unit level, million level and billion level.
1. 1.3. Numbers
1. 1.3. 1. How many digits does an integer have?
1.2. Pronunciation of large numbers
1.2. 1. Reading method 1
1.2. 1. 1. Put the number in the number table (right-aligned).
1.2. 1.2. Read the billion-level first, and then add the word "billion" after reading it.
1.2. 1.3. Read Wanji again, and add a word "Wan" after reading.
1.2. 1.4. Finally, look at a series.
1.2.2. Reading method 2
1.2.2. 1.4 bit classification
1.2.2. 1. Starting from the high position, read the billion series first, then the million series, and finally read a series.
1.2.3. Pronunciation with 0
1.2.3. 1. No matter how many zeros there are at the end of each stage, it will not be read.
1.2.3.2. A zero or consecutive zeros on other numbers can only be read by a zero.
1.2.3.3. Reading should be written, not mathematical words.
1.3. Writing of large numbers
1.3. 1. Method 1
1.3. 1. 1. Write according to the number table.
1.3. 1. 1.
1.3. 1.2. If there is no unit in a number, write a zero in this number.
1.3.2. Method 2
1.3.2. 1. Find the words "billion" and "million"
1.3.2.2. Write the billion series first (the number to the left of the word "billion")
1.3.2.3. Write another 10,000 series (numbers between "100 million" and "10,000")
1.3.2.4. Finally, write a series.
1.3.2.5. Except the highest level, each series must have 4 numbers. If it is less than 4 digits, add 0 before the number.
1.4. Comparison of large numbers
1.4. 1. Numeric number
1.4. 1. 1. The numbers are different.
1.4.1.1.1.
1.4. 1.2. Same number.
1.4. 1.2. 1. If they are the same, compare the next digit. ...
1.4.1.2.1.1.When the numbers are different,
One side of the number is larger.
1.4.2. Finishing
1.4.2. 1. Sort several numbers in descending or descending order.
1.4.2. 1. 1. Minimum quantity.
1.4.2. 1.2. Maximum quantity >; Second largest number > third largest number > ...> Minimum quantity
1.5. Large number rewriting
1.5. 1.0 integer, rewritten as a number in "ten thousand".
1.5. 1. 1. Remove the four zeros at the end and add a "ten thousand" after it.
1.5.2. The integer is rewritten as a number in "100 million".
1.5.2. 1. Remove the eight zeros at the end and add a word "billion" after it.
1.5.3. Attention
1.5.3. 1. The big number has been rewritten, and the size of the number has not changed. Use "=" to connect them.
1.6. Find the approximate figure.
1.6. 1. For non-integer tens, omit the mantissa after tens.
1.6.1.1.000 is 0 to 4.
1.6.1.1.1.directly remove all the numbers after 10,000 digits, and then write 10,000 words.
1.6. 1.2. Thousand is 5 to 9.
After the number1.6.1.2.1.0000, remove all digits after the number 10000, and write another ten thousand words.
1.6.2. For tens of thousands of non-integer bits, the mantissa after 1 100 million bits is omitted.
1.6.2.1.100000 digits are 0 to 4.
1.6.2. 1. 1.
1.6.2.2. Tens of millions are 5 to 9.
1.6.2.2. 1 .billion bits plus 1, after removing all the digits after one billion bits, write one billion words.
1.6.3. Attention
1.6.3. 1. When the divisor is found, the size of the number changes, so use ""to link it.
1.7. Generation of Numbers
1.7. 1. Ancient counting method
1.7. 1. 1 .physical count
1.7. 1.2. Number of knots
1.7. 1.3. Orbit counting
1.7.2. Notes
1.7.2. 1. Babylonian number
1.7.2.2. China number
1.7.2.3 Roman numerals
1.7.2.4. Arabic numerals (commonly used)
1.7.3. Natural number
1.7.3. 1.
1.7.3.1.1.1,2, 3, 4 ... all the objects are natural numbers.
1.7.3. 1.2. There is no object represented by 0.
1.7.3.2 features
1.7.3.2. 1. The smallest natural number is 0.
1.7.3.2.2. There is no maximum natural number.
1.7.3.2.3. The number of natural numbers is infinite.
The outline points are clearly written, the key points are clear, and the layout is novel and lively. Finally, pay attention to neatness and beauty, so that it can be made.