Math diary, fourth grade, 200 words.

April/kloc-light rain on Thursday, October 6th.

? Jingle bells. Jingle bells? School is over.

As soon as I got home, I took out the instruction series from my schoolbag without stopping. I did, and it will be finished soon.

When I started to check, I felt something was wrong when I checked the third sub-question of the third question. I checked it several times. 34=9 180 equals 9 180! Then I remembered a calculation method that Teacher Lin told us, 270? Don't look at the zero at 34, put 27? Write the number 34, and then add a zero after it. This number is the number of this question.

Friday, April 17, cloudy with light rain.

Today, I read a China folk song in a book. Is that what it says? A team of hunters, a team of dogs, two teams walk side by side, counting 360 heads and 890 feet. ? After reading it, I want to find out how many hunters and dogs there are. I did the math, but I just couldn't figure it out. At this time, my brother came and he explained it to me. It took me some time to come up with such a solution: The title tells us that a hunter and a dog have 360 heads. Suppose we take these 360 heads as dog heads, and each dog has four feet, then there should be 1440 feet (4? 360= 1440), but the title only told us that it was 890 feet, so I calculated 550 feet (1440-890=550). Why? Because the hunter has only two feet, I count him four. If two feet (hunters) are exchanged for four feet (dogs), two feet will be reduced, so how many two feet are included in the 550 feet, that is, how many hunters' two feet are counted as four feet.

Problem solving: Hunter: (4? 360-890)? (4-2)=275 (person)

Dog: 360-275=85 (only)

So there are 275 hunters and 85 dogs.

Monday, April 18, the weather is fine.

Did you do the last question in the second class of Independent Practice today? Practice and expand? . The topic is like this: Xiao Mahu regards 13 of a topic as 3 1, and the calculated answer is 450 more than the original one. I thought for a while, but I couldn't figure it out. After a while, I finally figured it out. Let me calculate 31-13 =18,450? 18=8 100, and then I put 8 100-450=7650. The next day, Independent Practice was published. I made a mistake on the last question. After the teacher answered, it turned out to be like this: 31-13 =18450? 18=25、25? 13=325。 I must carefully examine the questions in the future, or I will make mistakes again.

It will be cloudy on Wednesday, April 19.

Today is the measurement of the second unit angle in the math unit exam.

I worked hard on every problem until I worked it out? Draw a 3 cm line segment and extend it into a straight line? . This question puzzled me. At this moment, Mr. Lin said: skip the questions that can't be done first, and do other questions first, otherwise you will lose more points. . After listening to Mr. Lin's words, I'll do other problems at once. Just as I was doing the last question, the bell rang and I was going to hand in my paper. But I rushed to do that problem before I did it. I also briefly checked the paper and handed it to the group leader without any mistakes. Suddenly I felt that there was something wrong with that question, so I told the team leader:? Give it to me. ? She listened and said seriously: if you pay it, you can't pay it back! ? After listening to the group leader, I regret that I didn't check it carefully. I must learn from it in the future.

Mathematics comes from life.

Xiao Qiang runs 15 times around a flower bed with a diameter of 20m every day, so Xiao Qiang runs () km every day?

According to the formula for finding the circle, I quickly figured out that the answer should be 942. Feel good about yourself, put this data in brackets.

After reading it, the teacher only asked me, can I run so far in one day? I paused and suddenly realized.

It is true that mathematics is too closely related to life. Don't forget the reality of life just because you remember mathematics in your calculation. Always remember that mathematics comes from life.