1, get a preliminary understanding of negative numbers in familiar life situations, read and write positive numbers and negative numbers correctly, and know that 0 is neither positive nor negative.
2. Learn to express some practical problems in daily life with negative numbers, and experience the close relationship between mathematics and life.
I can learn to compare the sizes of positive numbers, 0 and negative numbers with the help of the number axis.
4. Knowing the image with positive proportional relationship, you can draw an image on grid paper with coordinate system according to the given data with positive proportional relationship, and you can calculate or estimate the value of the other quantity in the image according to one of them.
5. 16℃ is read as 16℃, which means16℃ above zero; -16℃ is read as minus 16℃, which means minus 16℃.
6. If 2000 means saving 2000 yuan, then -500 means spending 500 yuan. 3 meters east, marked as +3, 4 meters west, marked as -4.
7. On the number axis, the order from left to right is from small to large. 0 is the dividing point between positive and negative numbers, and all negative numbers are on the left of 0, that is, negative numbers are less than 0, positive numbers are greater than 0, and negative numbers are less than positive numbers. The larger the number after the minus sign, the smaller the number. For example: -8
9. A cone has only one bottom surface, and the bottom surface is a circle. The side of a cone is a curved surface.
10, the distance from the apex of the cone to the bottom center is the height of the cone. The cone has only one height. (Measuring the height of the cone: firstly, lay the bottom of the cone flat, place a flat plate on the top of the cone horizontally, and measure the distance between the flat plate and the bottom vertically).
1 1. Expand the side of the cone to get a sector.
12, understanding the meaning and basic nature of proportion, will be solution ratio.
13. If you understand the meaning of positive proportion and inverse proportion, you can find out the examples of positive proportion and inverse proportion in life, and you can use the knowledge of proportion to solve simple practical problems.