Current location - Training Enrollment Network - Mathematics courses - These four numbers can all be counted as 24 points.
These four numbers can all be counted as 24 points.
In a deck of cards (52 cards), 4 cards randomly selected have 1820 different combinations, of which 458 cards can't be counted as 24 points, such as A, A, A and 5.

Clever calculation of 24 points is a mathematical game, just like chess and go, and it is a kind of public entertainment.

It is unknown when it began, but it is gradually accepted by more and more people with its unique mathematical charm and rich connotation. This game is simple and easy to learn, and it is an extremely beneficial activity.

The content of the game "Clever 24 Points" is: take 52 cards from a deck of cards, randomly draw 4 cards (called a deck of cards) (only 40 cards of 1 ~ 10 can be used for initial training), and count the number on a deck of cards as 24 through addition, subtraction, multiplication and division (brackets can be added). Each card can only be used once. If the cards drawn are 3, 8, 8, 9, then the formula is (9-8) × 8× 3 or 3× 8+(9-8) or (9-8 ÷ 8 )× 3 and so on.

As a poker intelligence game, Count 24 points should also pay attention to skills in calculation. When calculating, it is impossible for us to try different combinations of the four numbers on the card surface, let alone touch them together. Here are some common methods that are easy to learn and master:

1. Solve with 3× 8 = 24 and 4× 6 = 24.

Try to sum the four numbers on the card face into 3 and 8, 4 and 6, and then multiply them to solve. For example, 3,3,6 and 10 can form (10-6 ÷ 3) × 3 = 24, etc. For example, 2, 3, 3 and 7 can form (7+3-2) × 3 = 24 and so on. Practice has proved that this method has the highest utilization rate and hit rate.

2. Use the operational characteristics of 0, 1 1 to solve it.

For example, 3, 4, 4 and 8 can form 3× 8+4-4 = 24. For another example, 4,5, j and k can form11× (5-4)+13 = 24 and so on.

3. In the deck with solutions, the following six solutions are widely used: (We use A, B, C and D to represent the four numbers on the deck)

①(a—b)×(c+d)

Such as (10-4) × (2+2) = 24, etc.

②(a+b)÷c×d

Such as (10+2) ÷ 2× 4 = 24, etc.

③(a-b÷c)×d

Such as (3-2 ÷ 2) × 12 = 24, etc.

④(a+b-c)×d

Such as (9+5-2) × 2 = 24, etc.

⑤a×b+c—d

Such as1/kloc-0 /× 3+l-10 = 24, etc.

⑥(a-b)×c+d

Such as (4-L) × 6+6 = 24, etc.

When students are playing games, they might as well try the above methods.

It should be noted that four cards (52 cards) in a deck can be randomly selected to have 1820 different combinations, among which 458 cards can't be counted as 24 points, such as A, A, A and 5.

It is not difficult to see that "calculating 24 points skillfully" can greatly mobilize the coordinated activities of eyes, brain, hands, mouth and ears, which is very helpful to cultivate our rapid mental arithmetic ability and reaction ability.

Children, please try "calculating 24 points skillfully". I believe you will like it soon.