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Mathematics teacher GBOU Lyceum No. 126 of St. Petersburg Gudkova Olga Viktorovna Multiplication and division decimals

Review What is decimal notation for fractional numbers? What are the places of decimal fractions? Name the rules for adding (subtracting) decimals Name the rules for multiplying decimals Name the rules for multiplying decimals by 10, 100, ...; to 0, 1; 0.01; ...

Oral calculations 3.08 + 0.2 2.54 + 0.06 8.2 – 2.2 6 – 0.02 4.7: 10 0.48: 4 0.9: 100 25.5: 25 0, 8:16

The following task will help you find out who is hiding under such an unusual name. 10 12.5 50 0.8 4000 1 0 100 0.1 0.008 0.5 0.008 40 1 0 1 BULK 0 0.5 1 0.008 40 1.125 0.01 0.1 CHR AE P E A H 100 × ? = Dermochelis ̶ what is it?

Dermochelis turtles live up to 200 years on the Pacific islands. They are so big that children can ride on their shells. This turtle is an excellent swimmer; its limbs have turned into flippers. Jewelry is made from the shell, and eggs and meat are eaten. How much does one such turtle weigh? It turns out that if you multiply this number by 0.024 and then subtract 3.227 from the product, you get 11.173. Let's solve this problem. Let x kg be the mass of the turtle. 0.024x – 3.227 = 11.173, 0.024x = 14.4, X = 600. Answer: 600 kg.

Calculate the value of the expression: a) 5.6 2 – 3.2 2 = b) (5.6 – 3.2)(5.6 + 3.2) = 31.36 – 10.2 = 21.12 2, 4 8.8 = 21.12 What did you notice? Write the equality in literal expression. a 2 – b 2 = (a + b)(a – b) Find the sum of the numbers: 0.1 + 0.2 + 0.3 + … + 1.8 + 1.9 + 2

(5.8 + 20)m 5.8m P = 2 × (a + b) P = 2 × (27.5 + 25.8) = 2 × 50.3 = 106.6 (m) (7.5 + 20)m Problem. Find the length of the fence surrounding a rectangular house, if the length of the house is 7.5 m, the width is 5.8 m, and the fence is placed at a distance of 10 meters from the house 7.5 m

Independent work 1) Calculate: 2.7 12 + 9936: 1000: 4.6 – 25.22: 26 2) Solve the equation: 21.87 – 323.91: x + 8.74 = 12.9

Answers 33.59 X=18.3

On the topic: methodological developments, presentations and notes

Objectives: Summarize the material studied. Consolidate knowledge, skills and abilities of adding and subtracting decimal fractions while solving problems. Expand interdisciplinary connections in the process of studying the...

This presentation is intended as accompanying material for the first lesson of studying the topic “Adding and subtracting decimals” in grade 5...

The most popular domestic reptiles in our country are turtles. Many owners of such animals are confident that keeping turtles is less burdensome than, for example, lizards or iguanas. This is the main reason for buying such a pet for children or simply as a beautiful living “toy” to satisfy aesthetic taste. However, the unpretentiousness of turtles is a myth, and when getting such a pet, it is important to know everything about the peculiarities of its life.

Turtles are certainly beautiful and interesting in their behavior animals of the order of reptiles. The main feature that distinguishes this type of reptile from other animals is the presence of a shell. This strong and “practical” armor consists of a lower part - the plastron and an upper part - the carapace. The shape, size, number of scutes and shell pattern are important species characteristics of turtles.

It was the shell, despite its heaviness, that helped this reptile survive for 175 million years. All modern turtles have retained their shell, although its shape and color differ from various types and depends on the habitat and method of existence of the animal. For example, at sea ​​turtles a significant part of the shell is missing, thanks to which these animals have learned to move quickly. Soft-bodied turtles have a round, frying pan-like shell that allows them to easily burrow into mud.

Over many millennia of existence, these beautiful animals have not changed much, but the numbers of some species have reached a critical level in recent centuries. That is why it is important not only to carefully monitor the health of your pet, regularly showing it to a veterinarian-herpetologist, but also to pay serious attention to the maintenance of the turtle, its diet, maintaining the temperature in the terrarium, and bathing. You cannot get a turtle without first preparing a specially designated place for it and without studying all the features of a turtle’s life.

The most common “domestic” reptiles are land and freshwater turtles. When breeding such animals, you need to know that most land animals are herbivores, and freshwater animals are predators and omnivores. Therefore, the former should not consume animal proteins (meat, eggs, cottage cheese, etc.). Their diet should consist of vegetables, fruits, berries, dandelion grass, clover, plantain. Conversely, the diet of freshwater animals should consist mainly of “animal food” such as snails, fish, squid, bloodworm shrimp, etc. For freshwater turtles, unlike land turtles, the industry produces a number of good dry foods (Sulfur, Tetra, etc.)

Freshwater turtles

The habitat of freshwater turtles is ponds, rivers, lakes and swamps. Such animals spend most of their time in the water, only occasionally climbing onto land to bask in the sun. The most popular types of turtles as pets are: Red-eared slider (Trachemys scripta); European marsh turtle (Emys orbicularis); Chinese trionix or Far Eastern turtle (Pelodiscus sinensis). When purchasing such reptiles, you need to know their characteristics and differences from each other.

The red-eared turtle can most often be found in aquatic terrariums. This is a very beautiful reptile with bright red, yellow and orange spots that are located on both sides of the head, resembling ears, for which the turtle earned its name. Young individuals up to six months have the brightest coloring than their older relatives. The upper part of their shell has a color from yellow-salad to emerald green. Over the years, it becomes olive or yellow-brown. In addition, on the shell there are patterns of bright yellow stripes and green circles.

This is a fairly active turtle, not only in water, but also on land. In addition, this beauty has very strong and sharp nails, which it often uses for self-defense. When removing a turtle from the terrarium, you should be wary of its hind legs; with them it will try to push off from your hands. And in general you should not bring it to your face or open areas of the body.

This is an aquatic turtle that prefers shallow water. She swims well, quickly moving her paws, and hides at the bottom, under stones, burrowing into the silt. Like most aquatic turtles, the European marsh turtle is a predator.

This turtle has an oval, smooth, dark olive-colored shell covered with yellow stripes and spots. The head, paws and neck are also dotted with large yellow dots; the shell is usually painted dark brown, less often yellow. The turtle has a long tail, which is approximately half the length of the shell, it serves as an additional “rudder” when swimming, the main tool for this is the hind limbs, and the fingers have rather long and sharp claws.

This turtle is an excellent swimmer and diver and can remain underwater for a long time. However, every 15-20 minutes, she needs to float to the surface to stock up on air. On land, European marsh turtles are not so active, but they still move faster than land turtles. On land they bask in the light for a long time, but at the slightest danger they hide in the water.

This turtle has a greenish-brown shell with a glossy surface. It reaches 25-30 cm in height, covered on top with soft skin without horny scutes. In young individuals, the “back” is covered with tubercles, which gradually disappear with age, and the shell takes on an almost flat appearance. Trionix's neck is very mobile and long, and its muzzle is elongated into a proboscis, at the end of which there are clearly visible nostrils. The powerful jaws of this predator have sharp cutting edges with which the turtle can inflict serious injuries, which makes it quite dangerous. Wounds after such “bites” do not heal well, so you need to be very careful when handling this pet. In addition, there are sharp claws on three toes, which also pose a threat. An unusual feature of Trionix is ​​additional skin respiration, along with pulmonary respiration.

According to amateurs, Chinese Trionix is ​​a very suitable candidate for keeping in a terrarium, since the ratio of water to land should be 5:1, and it is very convenient to observe the behavior of the turtle. However, it must be kept separately, since Trionix can pose a threat not only to its owners, but also to other soft-shelled turtles.

Land turtles

Land turtles live in steppes, forests and deserts. At a sufficiently high temperature, these animals actively move, since the processes in their body occur normally, and closer to winter they fall into suspended animation, that is, hibernation.

Such turtles feed on plant foods - any edible fruits and berries, cabbage, cucumbers, tomatoes, carrots (grated or thinly sliced), lettuce, dandelions, clover, some cruciferous plants (leaves, flowers), young tree leaves, but sometimes they also eat insects - earthworms, snails. Externally, land turtles are all similar, their differences being the coloring, shape of the shell, number and type of scutes and claws. The most popular as pets are:

Central Asian or steppe tortoises (Agronemys horsfieldii), Mediterranean tortoises (Testudo graeca), Balkan tortoise (Testudo hermanni), Egyptian tortoise (Testudo kleimanni).

As a pet, this is the most accessible animal of all reptiles; it can most often be found in terrariums. The size of such a turtle reaches 18-30 cm, its shell is relatively wide and round, colored in gray and green-yellow shades, the tail is thin and bony, in males it is much longer than in females. The forelimbs of such animals have four toes, and the toes of the hind paws are fused. Such turtles are quite slow and very hardy to unfavorable environmental conditions, which is probably what makes them the most popular.

Central Asian turtles rarely drink water, because in nature they have practically no access to it. If there is excess moisture, they urinate, but if there is no moisture, they can get by without excreting urine. Wherein humid environment can provoke the development of pathogenic bacteria in such animals, so it is enough to bathe such a turtle occasionally. Central Asian turtles love to dig holes, so it is best for them to lay the ground with large pebbles in a layer of at least 6-7 cm. Also, these turtles have great “claims” to light and ultraviolet radiation, which must be taken into account when creating a place of residence for them.

The shell of such a turtle is convex and high, it has a round-oval shape, usually slightly jagged at the edges. The size can reach 30 cm. The carapace has dark spots on a light olive or yellowish-brown background, which increase with age. Sometimes the spots merge, and the entire turtle acquires a dark, almost black color. There is one horny tubercle on the back side of the shell. The front feet of these turtles have five toes with claws. The tail is short and blunt. The head is covered on top with large symmetrical scutes. An interesting difference between these turtles is the “spurs” on the back of their thighs.

Mediterranean turtles live in dry steppes, semi-deserts and mountain slopes covered with bushes; this must be taken into account and added to the “interior” of the terrarium, for example, sprouted cereals, which are also eaten with pleasure by such a turtle. This animal is less “burrowing” compared to the Central Asian one, so the soil layer can be thinner, about 4-5 cm. Such turtles are active only in the morning and evening, at night and in the middle of the day they hide and even bury themselves.

There are two subspecies - western and eastern, they differ in size, the eastern Balkan tortoise is much larger. The main difference between these animals and their relatives is the conical spike at the tip of the tail, which is also slightly longer than that of other turtles. The high shell of such reptiles is usually 14-16 cm, but in rare cases reaches 20 cm. In young representatives of this breed, the upper part of the shell is colored brownish-yellow; in adults it darkens, and only a bright yellow border remains along the edge. Adult males are smaller than females, but their tails are longer and thicker.

In nature, the Balkan tortoise lives in dry steppes and bushes, which should be taken into account when creating living conditions for it in captivity. A very important factor for a comfortable existence is the humidity of the air and soil in the terrarium; the soil should not be allowed to be moistened by spilled water. drinking water. Such turtles are very active; in the spring, summer and autumn, in the mornings and evenings they move around their territory in search of a stranger. Balkan tortoises tend to live together, they even climb on top of each other, forming a pyramid, while the males like to “sort things out” by getting into a fight.

The Egyptian or Kleimann's tortoise is the smallest of all land tortoises. Its size is a maximum of 14 cm, while the length of the shell itself is 9-10 cm in length. Males are slightly smaller than females. The carapace is very convex yellow-green with a black stripe along the edges of the segments. There are black spots on the ventral scutes; such turtles have five toes with claws on their front paws.

The Egyptian tortoise is also original in its way of life. Unlike most turtles, it is active in winter and hibernates in summer. This is due to the fact that in the summer in the homeland of Egyptian tortoises there is intense heat, which they do not tolerate well. These animals prefer a diurnal lifestyle and can be kept in groups of several in a terrarium. Such reptiles live on average up to 30 years.

1. Palettes are applied to the figures. Calculate approximately the area of ​​these figures if the area of ​​each cell is 1 square. units

2. Place tracing paper on checkered paper and make a palette (e=1cm2). Draw some closed line on a piece of paper and find approximately the area of ​​the figure bounded by this line.

3. Draw a circle with a radius of 4 cm with a compass and use a palette to find the approximate area of ​​the resulting circle.

4. Quiz “I want to know everything.”

a) On the islands Pacific Ocean giant turtles live. They are so big that children can ride while sitting on their shell. Unscramble the name of the world's largest turtle by arranging the answers of the examples in descending order and matching them with the corresponding letters.

b) This turtle swims beautifully; its limbs have turned into flippers. Find the mass of the giant turtle in kilograms by calculating the sum of the roots of the two equations:

(x 6 - 956) : 4 = 70 and 328 - (y + 6) : 4 = 228.

c) Express the mass of the turtle in centners, in grams. What other units of mass do you know?

Lyceum /2007 academic year Teacher Rudakova T.F. Saratov 2007

Quiz “I want to know everything” Giant turtles live on the islands of the Pacific Ocean. They are so big that children can ride on their shells. To decipher the name of the world's largest turtle, solve the given examples and arrange the answers in descending order. E) :67; D) :42; C) 18450:246; X) 30240:63; M) 38640:48; P) 51750:25; I) 7912:86; L) :729; O) 24325:35 E) :328 DERMOCHELIS

At the board: X: 3 – 71 = 32 X:2=32+71 X:2 =103 X=103*2 X= :2-71=32 32=32 Answer: 206 Independently: (Y+6):4 =100 Y+6=100*4 Y+6=400 Y=400-6 Y=394 (394+6):4= =100 Answer: =600 Express the mass of the turtle in c., grams: 600 kg=6 c. , 600kg=g.

Solution to problem 207 Two cars left cities A and B, located 185 km from each other, simultaneously in opposite directions. One of them is at a speed of 95 km/h, the other is 90 km/h. How far apart will these cars be 6 hours after they start driving?

Analysis of the task: Is it possible to immediately answer the question posed in the task? Which car and why will it cover the greater distance? Solving a problem at the board using an expression. Task transformation. So what is the distance between the cars? (how far the CMs have moved away) Create a new condition on the moving diagram. How long will the cars take to travel?