Design concept

The weight of lighter items is usually expressed in grams and the letter "G". Grams and kilograms are commonly used units of mass, 1kg = 1000g, and the forward speed between them is1000g.

When converting from "kilogram" to "gram", add three zeros after the number, and when converting from "gram" to "kilogram", remove three zeros after the number. When weighing an object with a scale, the number of points pointed by the pointer indicates the weight of the object.

Introduction of teaching materials

Gram and kilogram are examples 1 and example 2 in Unit 8 of Grade Two Mathematics (Volume I) in the compulsory education textbook of People's Education Press. Students have previously learned the RMB unit Jiao Yuan fen, the length unit cm and m, and the time unit hour. This part of the textbook is basically the same as the length unit of the first volume of the second day of junior high school.

Although students have come into contact with the facts related to quality in their life and have a preliminary concept of the weight of an object, they still lack understanding of the quality unit because the quality unit is not as intuitive as the length unit and can only rely on the sensory perception of the body.

Therefore, students can intuitively perceive the actual "size" of 1g and 1kg through various activities, thus helping students to gradually establish a distinct "representation" and establish a good standard for subsequent reasonable estimation.