1, the single digits of two numbers are added. If the sum of single digits exceeds 10, it needs to be rounded. For example, numbers 23 and 47, the sum of single digits is 3+7= 10, which needs to be rounded.

2. Add the ten digits of two numbers. If the sum of ten digits exceeds 10, it needs to be rounded. For example, the numbers 23 and 47, the sum of ten digits is 2+4=6, and rounding is not needed.

3. Combine the sum of single digits and ten digits. If the sum of single digits exceeds 10, you need to add a carry to the ten digits. For example, the sum of the two numbers, 23 and 47, is 10. You need to add the decimal number to carry it to get the final answer of 50.

Here are some examples of quick calculation methods that combine head and tail:

1, calculate 23+47:

Single digit addition: 3+7 = 10, which needs to be rounded.

Ten digits add up: 2+4 = 6.

Combination result: 6 (ten digits)+1 (carry) = 7 (single digits).

The final answer: 73.

2. Calculate 58+32:

Single digit addition: 8+2 = 10, which needs rounding.

Ten digits add up: 5+3 = 8.

Combination result: 8 (ten digits)+1 (carry) = 9 (single digits).

The final answer: 90.

3. Calculate 97+82:

Single digit addition: 7+2 = 9.

Ten-digit addition: 9+8 = 17, which needs rounding.

Combination result: 1 (carry) +7 (decimal) = 8 (single digits).

The final answer: 100.

A good way to learn mathematics.

1, understand the concept

Make sure you understand the definition of every mathematical concept and the principle behind it, not just memorizing formulas and steps.

Step 2 do more exercises

Consolidate knowledge and improve skills through a lot of practice. Doing more exercises can help you get familiar with all kinds of problems and find your own weaknesses.

3, pay attention to the foundation

Mathematics is a progressive subject, which is based on basic knowledge. Make sure you have a solid understanding of basic concepts and skills, so that you can better understand and apply more advanced concepts.

Step 4 ask for help

Don't be afraid to ask for help if you encounter difficulties or don't understand a concept. You can ask teachers, classmates or parents for advice, or you can attend math tutorial classes or online learning resources.

5. Create application scenarios: connect mathematics with real-life problems and create application scenarios to solve problems. This can increase your interest in mathematics and help you better understand and apply mathematical knowledge.