Math diary, more than 300 words, speed 5

Mathematics is everywhere, there is a lot of mathematics around us, mathematics is indispensable, otherwise it will bring all kinds of things to life. Inconvenience, let's look for mathematics and explore mathematics together.

Circle", we can see it everywhere, isn't the bottom surface of the moon cake box, tea canister, and medicine box all round? However, they are called cylinders as a whole. Picking up these cylinders, you may think, why make the bottom surface round?

Why not make rectangles, squares? I used to doubt it, but now I can help you solve it!

If you make a box, a cube, and a cylinder with the same material, and then you calculate the volume, and we will find that the cylinder is the largest, the cube is the second, and the cuboid is the smallest. At this time, I understood, in order to save materials, I made these boxes round, so that the volume was also expanded.

That's the benefit of cylinders.

Today, my dad and I went to the bookstore to buy books.

We came to the bookstore. I picked out a book I had been looking forward to for a long time and went to the cash register. Dad said:

You are the yuan of this book, I am the yuan of this book, I take 3 more ballpoint pens, give 50 yuan and how many yuan is left? If you guess correctly, the rest of the money will buy you ice cream to eat. "I think:

The sum of 50 minus plus multiplying 3 is equal to yuan. I said, "Yuan."

Okay, I'll buy you ice cream for this yuan. Dad said cheerfully.

When I came to the ice cream shop, my father asked me again, "I bought 2 yuan of ice cream, I paid it, how much money is left?" "I think:

Simple, minus and multiply by 2, is equal to the yuan. I said, "There's still a dollar left."

Dad said, "Not bad! It's OK.

I said angrily, "You underestimate me, this is a two-year-old topic." If I don't know any of this, am I still a fifth-grader?

Mathematics is inseparable from life.

The math diary essay of about 300 words is as follows:

The first unit we learned this semester was cuboids and cubes, math diary composition. I learned this about the box: it has 12 edges, 6 faces, and 8 vertices;

The lengths of the three edges that intersect a vertex are the length, width, and height of the box, respectively. The length of each opposite edge is the same length, and the area of each opposite side is equal, if the area of one opposite side is square, the area of the remaining four faces is the same.

The formula for the surface area of a box is: length x width x2 length x height x2 width x height x2, and one is (length x width length x height width x height) x2. Its volume formula is: length x width x height.

The knowledge about the cube is that it has 12 edges of exactly the same length, 6 faces with a perfect area, and 8 vertices.

The formula for the surface area of the box is: edge length x edge length x6, and the volume formula is edge length x edge length x edge length. The formula for the unification of cubes and cuboids is: base area x height and cross-section area x length.

The thing about the volume is: the length of the volume is measured from the inside. 1 liter 1 cubic decimeter, 1 milliliter 1 cubic centimeter. The formula for calculating the volume is the same as for calculating the volume of a box.

If the problem asks you to find the volume unit, but the first step of the problem is to ask you to find the volume unit, you have to convert it from the volume unit to the volume unit. The near-green between volume units and volume units is 1000.