Ask for advice on the application of Olympic mathematics in the fourth grade of primary school (hypothesis method)

1. A school bought oranges, apples and pears for 352 yuan *** 100 Jin. It is known that oranges are 2 yuan per kilogram and apples and pears are 4 yuan per kilogram. It is also known that the cost of buying oranges and apples is more than that of buying pears in 24 yuan. So how many kilograms of apples do you buy?

The first step is to calculate the cost of buying pears.

(352-24)÷2= 164 yuan 164÷4=4 1 (kg)

Step two, ask about the cost of buying oranges and apples.

352- 164= 188 (yuan) 100-4 1=59 (kg)

The third step is to find the number of apples.

If you buy all 59 kilograms of oranges, the cost is 59×2= 1 18 yuan, 188- 165438 = 70 yuan.

70(4-2)= 35 (kg)

2. Liangliang and Cong Cong play the game of "Rock, Scissors and Paper". Two people take notes with the same number of stones. Lose once, give each other a stone. They played many games, among which Liang Liang won three times and Cong Cong added nine stones. How many games did they play?

The first step is to count the number of smart wins.

9+3= 12 times (12 winning stone minus 3 losing stone equals plus 9).

The second step is to count the number of games.

3+ 12= 15 times (the sum of the times won by two people is the total number of games).

3. How many tables does Party A have and how many chairs does Party B have? If Party B replaces all the chairs with the same number of tables, it needs to supplement Party A's 320 yuan. If Party B doesn't chip in, it needs to change five tables less. It is known that three tables are less than five chairs, 48 yuan. So, how many chairs does B have?

Step one, the price of each table

320÷5=64 yuan (the title condition can be understood as: 320 yuan can buy 5 tables).

The second step is the price of each chair.

(64×3+48)÷5=48 yuan.

The third step is the number of chairs.

320÷(64-48)=20.

4. If Party A and Party B shoot and hit, Party A will get 5 points and Party B will get 6 points; If you miss, A will lose 2 points and B will lose 3 points. Everyone played 10, and * * * played 15. As a result, A scored 3 points more than B. How many rounds did A and B play?

The equation can be obtained as follows: A 8 hair, B 7 hair.

If we don't list the equations, we haven't decided yet.