1. Swap the position of addend: during addition calculation, swap the positions of two addends and calculate again to see if the results of the two calculations are the same. If they are the same, the previous calculation is correct.

2. Subtract an addend from sum: Subtract an addend from the result of addition to see if it is equal to another addend. For example, the addition formula 3+4=7, and 7 MINUS 3 gets 4, which is the same as another addend, indicating that the original calculation is correct.

3. Check the carry of addend: besides checking, we should also pay attention to the carry problem. If there is no carry in the calculation, but there is carry in the calculation, it means that the previous calculation is wrong.

4. Reverse check: In some cases, you can use the method of reverse check to check the calculation. For example, the subtraction formula 7-3=4 can be used to add 3 to 4 to get 7, which is the same as the original formula, indicating that the original calculation is correct.

5. Double method: For some special addition formulas, double method can be used for checking calculation. For example, the addition formula 10+20=30, two addends can be multiplied by 2 to get 20+40=80, and then divided by 2 to get 30, which is the same as the original formula, indicating that the original calculation is correct.

Importance of checking calculation:

1. Ensure accuracy: In mathematical calculation, errors are common. By checking the calculation, we can check and ensure the accuracy of the calculation and avoid mistakes caused by carelessness.

2. Discover potential problems: Sometimes, mistakes or problems in calculation are not easy to be discovered immediately. By checking the calculation, you can check the calculation process of each step, so as to find potential problems or errors.

3. Strengthen understanding: checking calculation is not only a means of inspection, but also a means of understanding. Through checking calculation, we can understand the calculation process and steps more deeply and enhance our understanding of mathematical principles.

4. Improve self-confidence: Through inspection, you can have more confidence in your calculation results. When we know that our answers are correct, we will have more confidence in further study or practice.

5. Exam skills: In the math exam, checking calculation is necessary. Many questions need us to calculate. By checking and calculating, we can ensure that our answers are consistent with the standard answers and avoid losing points because of mistakes.