What do the numbers in the upper right corner and the lower right corner mean in mathematics? This is a problem in the primary school olympiad. A The number in the upper right corner is 2, and the number in the lower right corner is also 2. In mathematics, a number in the upper right corner and a number in the lower right corner represent the permutation calculation in mathematics.

1, the algorithm of "The number in the upper right corner of A is 2, and the number in the lower right corner is 2" is 2! = 2x 1 = 2；

2.a is the first letter of the arrangement, which is Permutation in English.

3. Use specific examples to illustrate the meaning of the expression: The possibility of the result of two children sitting on a stool is: 2! =2x 1=2 .

Extended data:

Basic counting principle and application of two commonly used arrays

1, addition principle sum classification counting method;

Each method in each class can accomplish this task independently; The specific methods in the two different methods are different from each other (that is, the classification is not heavy); Any method to accomplish this task belongs to a certain category (that is, classification does not leak).

2. Multiplication principle and step counting method:

One method of any step can't complete this task, and only by continuously completing these n steps can this task be completed; Each step is independent of each other; As long as the methods used in a step are different, the corresponding methods to complete it are also different.