20 10 12 19 Sunday sunny

Today, I have nothing to do at home, so my father gave me a question to do. The topic is: In a cage, how many chickens and rabbits are there? They have 35 heads and 94 feet. How many chickens and rabbits are there?

After dinner, I thought about it, but I couldn't think of it for a long time, so I answered with the hypothesis method: suppose these 35 heads are chickens, because chickens have two feet, so they are 35 × 2 = 70 (only). A few less than the total, namely: 94-70 = 24 (only). At this time, calculate its "big difference", and then calculate the difference between the number of legs of a chicken and a rabbit: 4-2 = 2 (only). At this time, even a little "small difference". Then divide "big difference" by "small difference": 24 ÷ 2 = 12 (pieces). Because all the heads are set to chickens, the result is only the number of rabbits The total of 35 minus 12 (the number of rabbits) is equal to 23 (the number of chickens).

So, A: 23 chickens and 0/2 rabbits.

Dad saw that my calculation was accurate and fast, and decided to give me another question. The topic is: Wang Li, 5 yuan and 2 yuan have 20 RMB, and one RMB is 82 yuan. How much RMB are there in 5 yuan and 2 yuan? Math diary in the sixth grade.

Although I usually do problems quickly, I am stumped now. It took me a long time to figure it out 5 yuan and 2 yuan are not chickens and rabbits. They have no legs and nothing. How to calculate?

Hey? Just thinking about this, I suddenly had inspiration. This is more than 5 yuan, isn't it equivalent to "rabbit legs"? 2 yuan less, equivalent to "chicken leg". Aren't these 20 cards equivalent to "the total number of heads" and 82 yuan equivalent to "the total number of feet"?

So, I did what I thought: First of all, I regarded all 20 as 5 yuan, that is, 20× 5 = 100 yuan. If we use 100-82 = 18 (yuan) again, it will be too much, which means "big difference". Then use 5-2 = 3 (yuan), which is their "small difference". Finally, divide "big difference" by "small difference", 18 ÷ 3 = 6 (Zhang), because it was set by 5 yuan before, so the result is from 2 yuan. Subtract 6 from 20 to get the number of 5 yuan (14).

A: 5 yuan has 14 RMB, and 2 yuan has 6 RMB.

Through the test of these two questions, I learned to use what I have learned flexibly and master the skills. When I encounter a problem, I should be good at understanding its meaning with my brain, rather than doing it blindly, so as to do it well.

In fact, as long as you use what you have learned flexibly and find the right method, there is no problem that cannot be solved.

In life, there is mathematics everywhere, and mathematics can be found everywhere. Mathematics is everywhere. Only by discovering and practicing by yourself can we have a deeper understanding. We should learn to feel the charm and fun of mathematics, enter mathematics, understand mathematics and answer questions in time, so as to learn mathematics well!

The second article: 400 words of math diary in the sixth grade

At noon, my father came back from work, humming a ditty, and happily stepped into the house. I greeted him and asked, "Dad, what's so happy today?" Dad said, "I got a raise this month." I asked, "How much salary do you get now?" Dad thought for a moment, smiled and said, "My salary is higher than your mother's. Our monthly salary adds up to 2800, and the monthly salary difference is 100. How much do you think I get a month? " "

After listening to my father's words, I began to draw a line graph on paper to help me understand: through observation and thinking, I quickly worked out the answer and told my father. First of all, mom's salary is as much as dad's, so mom and dad's monthly salary is (2800+ 100)=2900 yuan, and then the total monthly salary is divided into two parts, and 1 part is dad's monthly salary. The formula is: (2800+ 100)÷2= 1450 yuan.

Dad listened and nodded with satisfaction. At this time, my mother, who was cooking, said to me, "Do you have any other methods?" "Is there any other way?" I said in surprise. I stopped to observe and think curiously. I found that the key to this problem is to find out who is the standard. Different standards have different methods. So, I have a second method: taking mom's salary as the standard, assuming mom and dad's salary is the same, then the sum of their monthly salary is (2800- 100)=2700 yuan, and then divide the sum of monthly salary into two parts on average. 1 part is mom's monthly salary, and finally it is more than mom's 100. The formula is (2800-100) ÷ 2+100 =1450 yuan.