1, if you want to teach children the length in mathematics, you should first teach them the related concepts of length and learn the concepts of centimeters, decimeters and meters. And know the abbreviation of length unit.

2. Learning the length in mathematics is inseparable from the tools for measuring the length. Therefore, parents should let their children know the ruler and measure the length with it.

3. Learning the length in mathematics can't just stay in the concept. The most practical learning method is practical operation, comparing with the length of the object, so that children can understand the meaning of length.

4. Learn the length in mathematics, let the children know the concept of length with segments, let the children know the line segments, and know what the line segments mean to the length.

5. After understanding the concept and significance of line segments, we should teach children to use line segments, mainly knowing how to draw line segments and mastering the correct method of drawing line segments.

6. After learning and mastering the above-mentioned knowledge about length, children should be allowed to do more representative exercises about length, so that practice makes perfect and they can really learn the length in mathematics.