On the day of math diary 1 in Grade Two, I had nothing to do and wanted to help my aunt buy food. I thought I could finish math diary.
I came to the vegetable market and it was very lively. The noise is very annoying. I immediately bought my favorite chicken leg to eat. At this time, as soon as I realized the fragrance, I couldn't wait to pass. I immediately asked my boss a few dollars each, and the boss replied, "One from 4.5 yuan." I took out 10 yuan and gave it to him. He gave me the money and I left. I ran away without paying attention. When I went shopping, I found that I was 50 cents short, and I was going to change it. I was really confused at that time and immediately went to the place where I bought chicken. I am really careless at this time. Why didn't I notice? The boss is also warm-hearted. He gave me the money without saying anything. I bowed my head in shame, said "thank you" and left.
Later, I bought a lot of things, none of which counted. I decided to count patiently and finally got it. The answer is 45. 3 yuan. Dad told me how 50 yuan left only 4 yuan. What should I do? With a loss of 70 cents, what can I say?
As soon as I got home, I came to my father and said, "Dad, I'm sorry, I miscalculated the money." Dad smiled and said, "It doesn't matter. There must be careless mistakes in life. " I forgive you this time. Not next time. I heard what to say. Therefore, we should not make careless mistakes in general mathematics. If we make careless mistakes, we will suffer. You can't go shopping after that. Understand the last lesson.
Math diary Grade Two: My family bought a new house. Father asked me to calculate how many boxes of tiles and wooden floors I need to buy. 6 square decimeters per watt, one box of 20 yuan. Each wooden floor block is 18 square decimeter, and a box is 10.
I first measured the length and width of each room with a box ruler, and calculated the area of each room by multiplying the length by the width, because the kitchen and bathroom are tiled, and the two bathrooms plus the kitchen, the conclusion is:
4+3+9= 16 (square meter) 16 square meter = 1600 square decimeter.
1600÷6≈266 (block) 266 ≈ 20 ≈ 13 (box)
Mom's bedroom, my bedroom, study and living room add up:
16.8+28+16.5+16.7 = 78 (m2)
78 square meters =7800 square decimeters
7800÷ 18≈433 (block)
433÷ 10≈43 (box)
After I finished the calculation, I told my father to buy 3-5 more tiles and floors. As a backup, my father praised me for my calculation.
Math diary 3, a sophomore, is really happy today. My parents took me and my sister, which is the place we have been wanting to go for a long time.
At ten o'clock in the morning, we arrived at the subway station first. Four of us bought four tickets, two yuan each and eight yuan each, which was about 1800 yuan short. Because we had a feeling that we couldn't wait for the zoo, we got there soon. Because there are many people, you need to queue up to buy tickets. We saw the fare table. Thirty adults and fifteen children. Well, there are four of us, two adults and two children. It's not our turn to buy tickets yet. In fact, I have worked out in my mind how much we need to spend. Hey, hey, that's amazing. Sixty for two adults, thirty for two children and ninety yuan for four people. My parents also praised me for being great.
After entering the park, I took the cable car first, each person 10, and four people 40 yuan. On the cable car, I saw four big tigers, six little tigers, two lions, five ostriches, six alpacas, five foxes and two orangutans, but I won't mention many animals one by one.
At about 4: 30 in the afternoon, we reluctantly left the zoo and went to the subway station to buy tickets. When we got home, my father asked, are you happy today? My sister and I said happy with one voice! Finally, my father asked another question to see who would answer first, my sister or me. My father said how much did we spend on tickets today? I thought about it. Sixteen round-trip subway tickets, ninety zoo tickets and forty cable car tickets. Well, I answered 146 as soon as possible, and my dad finally gave me a thumbs up!
Math diary, Grade 2 and Grade 4, found an interesting math topic when she was doing her homework today: chickens and pigs are in the same cage, with a head of 10 and 32 legs. How many chickens and pigs are there? I thought and thought, looked and looked, calculated and calculated, but it was still wrong. Then my father came up to me and said, "How many legs do you think a chicken has less than a pig?"
"Article 2."
"Well, suppose 10 is full of chickens. How many legs does * * * have?"
"20 legs."
"Yes, how many legs are left after subtracting 20 legs from those 32 legs?"
12 legs. "
"Yes, this 12 leg is extra for pigs. Just now I said that pigs have two more legs than chickens, so divide by two. "
"Oh, I see. It is six pigs and four chickens. "
Dad reminds me, can I change my mind? Suppose 10 is all pigs? That's 40 legs. If you subtract 32 from 40, you'll lose 8 legs. Oh, all chickens. If you divide 8 by 2, you'll have 4 chickens and 6 pigs. According to the method my father taught me, I worked it out soon. I feel that mastering the method of doing math problems is very simple.
One day, my mother and I went shopping in grade two in math diary. Mom went into the supermarket to buy things and let me stand at the place where I paid.
I have nothing to do, just watch the assistant aunt collect money. After reading it, I suddenly found that the money collected by the assistant aunt was 1 yuan, 2 yuan, 5 yuan, 10 yuan, 20 yuan and 50 yuan. I feel very strange: Why isn't RMB from 3 yuan, 4 yuan, 6 yuan, 7 yuan, 8 yuan, 9 yuan or 30 yuan, 40 yuan or 60 yuan? I ran to ask my mother, and my mother encouraged me to say, "Think hard and calculate well. At this time, my mother believes that you can figure out the reason. " I calmed down and thought it over. After a while, I jumped up happily: "I see, because as long as there is 1 yuan, 2 yuan, 5 yuan, 3 yuan, 4 yuan, 6 yuan, 7 yuan, 8 yuan and 9 yuan can be combined at will, and as long as there is1yuan, 20 yuan and 50 yuan, they can also be combined into 30 yuan, 40 yuan and 60 yuan."
My mother nodded straight and asked me another question: "If we just want to combine at will, isn't 1 yuan enough at this time?" Why 2 yuan and 5 yuan? "I said," it is not convenient to use 1 yuan to form a larger number. "Now my mother showed a satisfied smile and praised me for observing more and thinking more. I am really more comfortable than eating my favorite ice cream.
Here, I also want to tell other children: in fact, there are math problems everywhere in life. As long as you pay more attention to observation and thinking, you will find many unexpected discoveries. Try it if you don't believe me!