After cutting off a 6 cm long cuboid from one end of a cuboid block, a cuboid is exactly obtained. The surface area of this cuboid is 120 square centimeters less than that of the original cuboid. What is the volume of the original cuboid?

Let the edge length of the cut cube be x cm, then the length of the original cuboid is (x + 6) cm, and the length of the width and height are x cm. From the title: 2x2 + 2x (x + 6) + 2x (x + 6) = 6x2 + 120, the solution is: x = 5. The width and height of the original cuboid are: 5 cm, the length of the original cuboid are: 6 + 5 = 11 (CM), 11 × 5 × 5 = 275 (CC). Answer: the volume of the original cuboid is 275 CC

Summer vacation homework of grade 5 Volume 2

The answer is 2009940. If you don't believe me, just do it by yourself. That's how I wrote our math summer homework. We all have answers in all aspects of thinking. Don't believe me, and

Write the formula and thought
1. Wang Jun has some chess pieces. The number of sunspots is twice that of white pieces. Four black pieces and three white pieces are taken each time. After the white pieces are taken, there are 16 sunspots left. How many are the original sunspots of Wang Jun?
2. The charging standard of a city's internal telephone is: 0.20 yuan for the first three minutes (if not, it will be calculated as 3 minutes), 0.30 yuan for every minute after that, and 0.08 yuan for every ten seconds (if not, it will be calculated as 10 seconds). Li Li made several calls a day, and he had to pay 1.84 yuan. How many minutes did Li make the most calls?

Suppose that there are x white, then there are 2x black. For every 3 white sunspots reduced, there are 4 corresponding sunspots reduced. When x white sunspots reduced, then there are 4x / 3 sunspots reduced, so there are (2x-4x / 3) = 2x / 3 sunspots left. From the meaning of the question, we get 2x / 3 = 16, so x = 24, that is, 24 white sunspots, so there are 48 sunspots
Because the charge standard for making local calls is lower than that for making long-distance calls, it is necessary to make as many local calls as possible "how many minutes at most". Because the charge standard for making local calls is "0.2 yuan for the first three minutes, and 0.1 yuan for every one minute later". If all local calls are made, it is impossible to have "6 points" for the last number of calls, Then 1.96 yuan includes at least 20 seconds of long-distance call charge: 0.08 × 2 = 0? 16 (yuan), then the total local call charge: 1.96-0.16 = 1.8 (yuan)
Considering that the average telephone charge in the first three minutes is less than 0.1 yuan per minute, if it is more than three minutes later, 0.1 yuan will be added for each call, so it is most cost-effective for each call to take exactly three minutes, then the maximum telephone charge of 1.8 yuan is 8 △ 0? 2 × 3 = 27 (minutes)

Find the sum of all negative integers with absolute value less than 7 and greater than 3

It's (- 6) + (- 5) + (- 4) = - 15

Summary of the definition of mathematics in Grade Seven

Mathematics in the first grade of junior high school Volume 2 summary of knowledge points: Chapter 5 triangle
1、 Triangle and its related concepts
1. Triangle:
A triangle consists of three line segments which are not on the same line. The line segments that make up the triangle are called the sides of the triangle. The common ends of the two adjacent sides are called the vertices of the triangle. The angle formed by the two adjacent sides is called the inner angle of the triangle, which is called the angle of the triangle for short
2. Representation of triangles:
Triangles are represented by the symbol. Triangles whose vertices are a, B and C are recorded as ABC and read as ABC
3. The trilateral relationship of triangle is as follows
(1) The sum of the two sides of a triangle is greater than the third
(2) The difference between the two sides of a triangle is less than the third
(3) Function:
① Judge whether three known line segments can form a triangle
② When both sides are known, the range of the third side can be determined
③ Prove the unequal relation of line segments
4. The relationship between the internal angles of triangles:
(1) The sum of the three internal angles of a triangle is 180 degrees
(2) The two acute angles of a right triangle complement each other
5. Stability of triangles:
The shape of a triangle is fixed. This property of a triangle is called the stability of a triangle
6. Classification of triangles:
(1) Triangles are classified by edges
Unequal triangle
An isosceles triangle whose base and waist are not equal
an isosceles triangle
Equilateral triangle
(2) Triangles are classified by angle
Right triangle (a triangle with a right angle)
Triangle acute angle triangle
Oblique triangle
Obtuse triangle (a triangle with an obtuse angle)
Connecting edges and angles, we have a special triangle: isosceles right triangle. It is a right triangle with two equal right sides
7. There are three important segments of a triangle
(1) Angle bisector of triangle:
Definition: in a triangle, the bisector of an internal angle intersects its opposite side. The line segment between the vertex of the angle and the intersection is called the angle bisector of the triangle
Properties: the three bisectors of the triangle intersect at one point. The intersection point is inside the triangle
(2) The middle line of the triangle:
Definition: in a triangle, the line connecting a vertex and the midpoint of its opposite side is called the middle line of the triangle
Properties: the three middle lines of the triangle intersect at one point, and the intersection point is inside the triangle
(3) High line of triangle:
Definition: make a vertical line from a vertex of a triangle to its opposite line. The line between the vertex and the perpendicular foot is called the high line of the triangle
Properties: the three high lines of a triangle intersect at one point. The intersection of the three high lines of an acute triangle is inside it. The intersection of the three high lines of a right triangle is the midpoint of its hypotenuse. The intersection of the three high lines of an obtuse triangle is outside it;
8. Area of triangle:
Area of triangle = × base × height
2、 Congruent graph:
Definition: two figures that can completely coincide are called congruent figures
Properties: congruent graphs have the same shape and size
3、 Congruent triangle
1. Congruent triangles and related concepts:
When two triangles are congruent, the overlapped vertex is called the corresponding vertex, the overlapped edge is called the corresponding edge, and the overlapped angle is called the corresponding angle
2. Representation of congruent triangles:
Congruence is represented by the symbol "≌", read as "all equal". For example, △ ABC ≌ △ def, read as "triangle ABC all equal to triangle def"
Note: when two congruent triangles are recorded, the letter representing the corresponding vertex is usually written on the corresponding position
3. Properties of congruent triangles: the corresponding sides and angles of congruent triangles are equal
4. The determination of congruence of triangles is as follows
(1) Edge: the congruence of two triangles with three corresponding equal sides
(2) Angle, edge and angle: the congruence of two triangles corresponding to two angles and their clamped edges (can be simply written as "angle, edge and angle" or "ASA")
(3) Corner edge: the congruence of two equal triangles corresponding to two corners and the opposite side of one corner (it can be simply written as "corner edge" or "AAS")
(4) Corner edge: two congruent triangles with equal angles between the two sides (can be written as "corner edge" or "SAS")
The judgement of congruence of right triangle is as follows
For special right triangles, when they are congruent, there is HL theorem (hypotenuse, right edge theorem): hypotenuse and a right edge correspond to the congruence of two equal right triangles (which can be simply written as "hypotenuse, right edge" or "HL")

There are two kinds of boxes: box a and box B. If box a is divided into 8 boxes, box a and Box B are equal. If Box B is divided into 14 boxes, box a is twice as big as box B. how many boxes are there?

Let B be x, then a = x + 16, so x + 16 + 14 = 2 (x-14) gives x = 58, so a = 74

How many meters is a square meter

One square meter = 1 meter * 1 meter

The quality inspection department inspected a batch of parts, and found that the qualified rate of these parts was 96%. There were 6 unqualified parts. How many of these parts?

6 divided by (1-96%) = 150. You ask for the unqualified rate, and then divide the unqualified rate by the number of unqualified parts

Please,
I'm on the third day of junior high school this year, and I'm on the top of my grade, but I can't do math application problems, such as profit, growth rate, income, loss be utterly ignorant of.

Read more books
Solving practical problems with equations
The first step: read the title and find out what is known and what is required;
The second step is to find out the equal relation or unequal relation;
The third step: set up the unknowns, and list the equations (or inequalities) according to the equal or unequal relations;
Step 4: solve the equation or inequality, and check whether it meets the actual requirements

How many liters is a cubic centimeter

One cubic centimeter = 1 ml
1 liter = 1000 ml
therefore
One cubic centimeter equals 0.000 liters

After cutting off a 6 cm long cuboid from one end of a cuboid block, a cuboid is exactly obtained. The surface area of this cuboid is 120 square centimeters less than that of the original cuboid. What is the volume of the original cuboid?