1, 100000 is,1000000 is10/0.

One (one).

2. Representing the number of objects are 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,1,which is represented by 0. 0 is also a natural number.

0, the number of natural numbers is

3, the ratio between two counting units is

5. How to read three levels of numbers:

(1) Starting from high school, read hundreds of millions, then tens of thousands and finally grades.

(2) Numbers on billion (or ten thousand) levels are read according to the individual reading method, and numbers on billion (or ten thousand) levels are read with the word "hundred million" (or "ten thousand").

③ Don't read the "0" at the end of each level.

④ No matter how many zeros are in the middle of each stage, only one zero is read.

6. How to write a number with three levels:

(1) From top to bottom, write billions first, then tens of thousands, and finally levels.

(2) Which number has several counting units, write a few on this number.

③ If there is no counting unit on any number, write "0" on the number.

7. Method of comparing large numbers:

(1) has many digits.

(2) If the digits are the same, the number with the largest digit from the left is the largest; If the first place from the left is the same, look at the second place.

8. How to rewrite an integer into a number with the unit of "ten thousand": remove the "0" at each level and rewrite it into the word "ten thousand".

The method of rewriting an integer into a number with "100 million" as the unit: remove eight "0s" at the level of 10,000 and rewrite it into the word "100 million".

9. Get a rough figure by rounding: whether it is "rounding" or "decimal" depends on the highest digit of the mantissa omitted. If it is less than 5, it is completely rounded and rewritten as 0; If it is greater than or equal to 5, enter 1 bit forward, then discard it and the number on the right and rewrite it as 0.

Unit 2: Angle Measurement

1, the straight line segment has two endpoints, and the length can be measured.