In this lesson, you will learn about "written addition and subtraction," one of the most important topics in numbers and calculations. The goal is not simply to memorize terms, but to be able to explain the mechanisms and reasons in your own words.
Key Point
When the same place values are aligned vertically, you can see how collecting 10 units sends one unit to the next higher place.
When the same place values are aligned vertically, you can see how collecting 10 units sends one unit to the next higher place.
Points to Remember
- Check not only the conclusion but also the reasons behind it
- Distinguish similar terms and exceptions
- Try applying the same way of thinking to other examples
Practice
- Explain the key point in two sentences.
- Give one common misconception and explain what is different about it.
- Check it by applying it to a familiar or specific example.