1, 1,2,6, (), (). Find the law and tell me what it is.

Analysis:

1= 1x 1

2= 1x2

6=2x3

24=6x4

120=24x5

Extended data:

Find a routine method:

1, serial number: to find a regular topic, a series of quantities arranged in a certain order are usually given, and we are required to find a general rule according to these known quantities. Find out the rule, usually the serial number of the package. Therefore, it is easier to find the mystery by comparing variables with serial numbers.

2. Fibonacci sequence method: each number is the sum of the first two numbers.

3. Arithmetic series method: the difference between every two numbers is equal.

4. Tabbing method: You can look at it every once in a while to see what the relationship between the separated numbers is, for example, 14, 1, 12, 3, 10, 5, odd items become arithmetic progression, even items also become arithmetic progression, and then you have to fill in 8.

5. Incremental method: See if the difference between every two numbers is arithmetic progression, such as 1, 4, 8, 13, 19, and the difference between every two numbers is 3, 4, 5 and 6 respectively, so the next difference should be 7, that is, 26.