1. Abstract In our life, the game "2 1 point" has been widely known. From 1 to 10, arbitrarily select four numbers, and use the operation symbols of+,-,×, and () to make the sum-difference product quotient equal to 24. So, how to calculate "24 points" more easily? For example, the following numbers: 4, 3, 3, 6 algorithm: (3÷3×4)×6=24, and for example: 5, 1, 8, 3 algorithm: 5× 3+ 1+8 = 24. Second, the question is raised &; The purpose of the query is to assume four natural numbers, A ≤ 10, B ≤ 10, C ≤ 10 and D ≤ 10. So, how to quickly use these four numbers+,-,× and () to make their sum-product quotient equal to 24? When it is equal to n. Third, look at several groups of examples in the inquiry process: digital methods 9, 5, 3, 4 (5× 3-9 )× 43, 3, 6, 8 (3× 3-6 )× 86, 8, 5, 4 (5+4-6 )× 83, 7, 5, 6 [5] c？ d)×a=24(？ For a, b, c and d, there are 16896 possibilities. According to incomplete statistics, this is the most likely one. 2, a, b, c and d, where if a is a divisor of 24, but (b? c？ D)×a≠24, priority should be given to (A? b)？ (c？ D) or (a)? b)？ (c？ D)=24. According to incomplete statistics, a× b-c× d and (a b)? The probability of (c d) is higher (? Is one of+,-,× and \u). In the same way, it is extended to any four natural numbers A, B, C and D less than 10, so that their sum-difference product quotient is equal to n. If n is a composite number, then (b? c？ D)×a=n and (a? b)？ (c？ D) or (a)? b)？ (c？ D)=n, these two combinations are the most likely. According to incomplete statistics, the more divisors of n, the greater the two possibilities. (? As one of+,-and× 3, the most likely situation is (incomplete statistics) (1) (a-b )× (c+d) (2) (b+c) ÷ d× a (3) (b-c). 6, 5, 16× 5+ 1-77, 4, 7, 37× 4+3-79, 6, 4, 59+6+4+59, 3, 1, 4 (4+65433 So, I made the following kinds of induction: 1, if a? B=24, c=d, so there is another one? b+c-d=24(？ Is it one of+,-,×, or before and after? For the same operation symbol) 2. If a? B=25, c=d, then there is (a? b)×c÷d=24(？ Is it one of+,-,×, or before and after? For the same operation symbol) 3. Generalize it to any four natural numbers A, B, C and D less than 10 in the same way, so that their sum-difference product quotient is equal to the smaller the divisor of n. n, then (a? b？ C) d and (a? B) The higher the probability of (c, d). (? It is one of+,-,× and ÷) 4. According to incomplete statistics, the following two algorithms are more likely. (1) A × B+C-D (2) (A-B) × C+D After accurate calculation by computer, four cards were randomly selected from a deck of cards (52 cards), and there were 1820 different combinations, among which 458 cards could not be counted as 24 points. List several situations: 65438. 65, 5, 5, k, where k≠ 1, 4, 5, 6, 96, 6, 77, 7, k, where k≠3, 48, 8, 8, k, where k=7, 8, 97.