1. It is easy for underage cats to judge their age according to their teeth, but it is difficult for adult cats to judge their age according to their teeth because their teeth have not changed obviously.

2. You can usually open the cat's mouth to see if there are any teeth on the gums.

3. If the surface can't see the teeth temporarily, it's usually about 1- 15 days.

4. If you have begun to grow teeth, and the teeth are irregularly arranged and have different sizes, it is usually about 20 days.

5. If the front teeth of deciduous teeth are long, the number of teeth is 28, usually about 4-6 weeks.

6. If the cat has replaced the first deciduous incisor, it usually takes about 2-6 months.

7. If the permanent teeth are all long, the number of permanent teeth of a cat is 42, which means that the age of the cat is 1 year, which is often called an adult cat.