One day, my mother and I went shopping. My mother went into the supermarket to buy things and let me stand where I paid. I have nothing to do but watch my assistant aunt collect money. Looking at 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 think it's strange: why RMB? I hurried to ask my mother, who encouraged me to say, Think about it and do the math, mom. I'm sure you can find out why. I calmed down and thought it over.

After a while, I jumped up happily. I see, because as long as you have 1 yuan, 2 yuan and 5 yuan, you can form 3 yuan, 4 yuan, 6 yuan, 7 yuan, 8 yuan and 9 yuan at will, and as long as you have 10 yuan, 20 yuan, 50 yuan, you can also form yuan, 40 yuan and 60 yuan? Mom nodded straight and asked me another question: Isn't 1 yuan enough if it's just for random combination? Why 5 yuan, 2 yuan? I said:? It is not convenient to use 1 yuan to form a larger number. Now my mother shows a satisfied smile and praises me for observing well and using my brain well. 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!

The Chinese New Year is coming, and my mother is going to buy a box of chocolates for her relatives. We came to the supermarket. However, there are many varieties and prices of chocolate, and the packaging is beautiful, which is really dazzling. Finally, we decided to choose a box in Ferrero. A box of chocolates16 is 44.8 yuan, another box of chocolates is 3 pieces of 8.6 yuan, and another box of chocolates is 24 pieces of 70 yuan.

Mom asked me:? Which is more cost-effective? I thought of two ways.

Method 1: Calculate the price of each one. 44.8? 16=2.8 (yuan) 8.6? 3? 2.86 (yuan) 70? 24? 3 (yuan) 2.8 yuan < 2.86 yuan

16 PCs is more economical. Method 2: Calculate how much 1 yuan can buy. 16? 44.8? 0.36) 3? 8.6? 0.35 (piece) 24? 70? 0.34 (PCs) 0.36 PCs > 0.35 PCs > 0.34 or 16 is a good idea.

? Mom, 16 has the highest cost performance. Let's leave this box at home later! Ok, Kiki, we will save money in the future! ?

So, my mother bought 16 chocolate, which was 0.06 yuan cheaper than 3 chocolates and 24 chocolates. It's really cost-effective, economical and delicious. Next time, I will save money for my mother.

Today, my mother is doing housework and I am doing my homework.

I found that I couldn't do a math problem, so I just sat there. Ha, after the test paper was finished, I began to think about this problem slowly. The topic is:? A classroom is 8 meters long and 6 meters wide, and the floor is paved with square floor tiles with a side length of 4 square decimeters. I thought about how many such tiles I need for a while, and then I understood. I brushed a few strokes on the paper, and my mother shook her head and said slowly, No, think again. ? I racked my brains, but I still couldn't figure it out. I said, Mom, please give me a break! ? My mother began to teach me seriously: Do you think 1 meter and 1 square meter can be compared? I can't! ? I said. ? What does this have to do with the topic? Then what you distinguish is wrong. Look, you don't know the area of this floor tile! Isn't it? I nodded, as if I understood. So, I wrote on the test paper again.

It turns out that doing math problems is not just looking at numbers. It is the same as writing a composition. We have to examine the problem first, then check it, and make the whole problem completely clear before we can start to do it. This is my little discovery in doing math problems!

Math paper 300 words four saw a small math problem in a book today:? Xiao Ming has 10 balloons. If he flies a balloon every minute, he flies 10 balloons. * * * I spent a few minutes deliberately testing my sister. My sister, who just entered the fourth grade, said without thinking. This is simple, 10 minutes. ? I laughed and shouted:? No! Hmm? Why? I patiently explained: the answer is 9 minutes, because the first balloon will be released first, and the second balloon will be released one minute later until the ninth balloon is released, so the 10 balloon will be released after the ninth minute. ? My sister suddenly realized and said: I see! I was cheated! ?

Mother listened carefully to our interesting conversation and said with a smile. In fact, there are many such problems in life, such as climbing stairs, queuing and occupying seats. Let me test you! It took my sister nine seconds to walk from the first floor to the second floor, so how many seconds did it take her to walk from 1 floor to 15 floor? I took out a pen and did it carefully: it took my sister nine seconds to get from the first floor to the second floor, and my sister walked to the fifteenth floor, which means she walked fourteen floors. 14*9= 126 seconds.

I told my mother the answer, and she smiled and said, OK, clear thinking, clear thinking! ?

Yes, there are numbers everywhere in life. As long as we have a pair of observant eyes and a thinking mind, many problems can be solved easily.