Unit 1? Length unit: 1. cm，m？ m

We have learned two commonly used units (centimeter) and (meter). ?

2、 1 m = 100 cm， 100 cm = 1 m，？

3.？ A ruler is a tool for measuring (length).

4.？ A relatively small object can be measured in centimeters. ?

5.？ Mass objects are usually measured in meters. ?

6. The line segment is (straight) and has (two) endpoints. ?

7. The line segment is (straight) and the length can be measured.

8. A triangle consists of (3) line segments and a square consists of (4) line segments.

9. You can draw (1) line segments between two points, with different lengths. ?

10. To know the length of an object, you can use (? Ruler? ) to measure ?

1 1. To measure the length of an object, generally put a ruler (? 0? ) The scale is aligned with the left end of the object.

Unit 2? The addition and subtraction within 100 (2) 1 (same digit) should be aligned, starting with (single digit); The digits add up to ten. Enter 1 (ten digits). ?

2. (Same digit) should be aligned, starting with (one digit); If the number of digits is not enough, subtract 1 from (ten digits).

3. When calculating the addition and subtraction of two digits with a pen, it will be reduced from (digits). ?

4. Appendix+Appendix = sum, minus-minus = difference.

Unit 3? The unit of length is 1, and an angle has (1) vertices and (two) edges; Both sides are (straight), starting from the vertex.

2. The angle has nothing to do with the length of the side, but it is related to the opening degree of both sides. The larger the openings on both sides of the angle, the greater the angle; The smaller the opening, the smaller the angle.

3, draw the corner to remember: first draw the vertex and then draw the edge; When drawing an angle, draw (two) straight lines in different directions from a (point) and draw a (angle). ?

4. Method of measuring right angles: Vertex to vertex, one side to one side, to see if the other side coincides, coincidence is right angles, and non-coincidence is not right angles.

5. Based on the right angle, the angle less than the right angle is (acute angle); An angle greater than a right angle is (obtuse).

6. When the clock faces are (3) and (9), the hour hand and the minute hand form a (straight) angle.

7. A rectangle and a square each have (4) angles, and both are (straight) angles.

8. A triangle has (3) angles; A triangular ruler has (3) angles, (1) right angles and (2) acute angles.

9. A triangular ruler has (one) right angle and (two) acute angles. ?

10, all right angles are (same size).

1 1. Each triangle has (3) angles and (1) right angles, and the other two angles are less than right angles.

12. There are (4) corners on the cover and blackboard of the math book, all of which are (straight) corners.

13, a rectangle has (4) corners, and (4) corners are right angles.

14, take a piece of paper, first fold it up and down, then fold it (left and right) at right angles.

Units 4 and 6? Table multiplication? 1, multiplier × multiplier = product?

2. Factor × factor = product?

3. How many times is the sum of times?

4. How many times are you multiplied by?

5. How many times did you visit? 6. A few add up to a few.

Unit 5? Observe the object 1. We have learned four kinds of solid figures: (cuboid), (cube), (cylinder) and (ball).

2. One face of the three-dimensional figure you see is a rectangle. This geometry can be (cuboid) or (cylinder).

3. One face of the three-dimensional figure you see is round. This geometry can be (cylindrical) or (spherical).

4. One side of the three-dimensional figure you see is a square. This geometry may be (cube) or (cuboid).

Unit 7? The recognition time is 1, the short time is (hour hand) and the long time is (minute hand). ? The minute hand points (12) and the hour hand points for several hours. ?

2. Look first (hour hand) and then (minute hand). ?

3. 1 =(60) points? When 60 points =( 1)?

4. (30) minutes can also be said to be (half) hours, and (15) minutes can be said to be (an instant).

5. The minute hand walks at 1 Yes (1), the minute hand walks at 1 Yes (5), and the minute hand walks once (60); Walking one square clockwise is (1) hours. ?

6. There are (12) big squares on the clock face, and each big square is divided into (5) small squares. There are (60) squares on the clock face. ?

7. When the hour hand goes 1 hour, the minute hand just goes (60) minutes, which is (1) hours.

8. (12) when all three hands on the clock face coincide, and (6) when the hour hand and the minute hand on the clock face are in a straight line. ?

9. "After a few minutes" and "After" are added; Subtraction was used before.

10, which is (60) when the minute hand turns once, that is, (1); When the clockwise circle is (12).

Unit 8? Permutation and combination 1,? Every two people shake hands 1 time, and three people shake hands * * * (3 times). ?

2、? Every two people hold 1 time, and four people hold * * * (6 times). ?

3、? Every two people hold hands 1 time, and five people hold hands * * * (10/time).