What's the meaning of M5 in M5 cement mortar masonry exterior wall What's the meaning of M5 in M5 cement mortar Is the strength grade of mortar the same as that of concrete? Many brothers are right, but they can only choose one answer ~ then I have to choose the first one to tell me ~ other brothers, I can only say sorry ~ if I can choose all of you, I will choose all of you~

What's the meaning of M5 in M5 cement mortar masonry exterior wall What's the meaning of M5 in M5 cement mortar Is the strength grade of mortar the same as that of concrete? Many brothers are right, but they can only choose one answer ~ then I have to choose the first one to tell me ~ other brothers, I can only say sorry ~ if I can choose all of you, I will choose all of you~

Strength grade of mortar
Generally speaking, it is the same in meaning, but the materials used are different with different proportions. The mortar strength grades generally include M2.5, M5, M7.5, M15, and the mortar grade of masonry block is replaced by MB. The others are exactly the same. The concrete strength grade starts from C15 to C80, and each difference of 5 is a grade

Is the cement mortar of 1:2.5 mass ratio or volume ratio? How do we mix with shovel on the construction site?

1: 2.5 may be the mass (weight) ratio or the volume ratio, but without explanation, it is the mass ratio. The mass ratio of cement and sand is 1:2.5
The shovel can mix cement and sand, or it can be turned.

1: Is the volume ratio or mass ratio of dry and hard cement mortar

Volume ratio
Generally, the proportion of stressed components in structure is the weight ratio, and the volume ratio in building decoration (putty is the weight ratio)

A mathematical problem about derivative function
Let f (x) = A / 2 × x ^ 2 + (x + 1) / e ^ X-1. (1) if a = 0, find the monotone interval of F (x). (2) if x ≥ 0, f (x) ≥ 0 holds, find the value range of A
Notice the function f (x) = (A / 2 times x ^ 2) plus (x + 1) / e ^ x minus 1

Let f (x) = (A / 2) x & sup2; + [(x + 1) / e ^ x] - 1. (1) if a = 0, find the monotone interval of F (x). (2) if x ≥ 0, f (x) ≥ 0 holds, find the value range of A. (1) when a = 0, f (x) = (x + 1) / e ^ X-1. Let f ′ (x) = [e ^ X - (x + 1) e ^ x] / e ^ (2x) = - x (e ^ x) / e ^ (2x) = - X / e ^ x = 0, get the stagnation point x =

There are 270 students in the sixth grade of a school. One fourth of the boys are equal to one fifth of the girls. There are boys and girls in the sixth grade of the school
Write out the process of calculation

Male 270 ^ (1 + 1 / 4 ^ 1 / 5)
=270÷（1+5/4）
=270÷9/4
=120 people
270-120 girls = 150

Given that when x = 2, the value of the algebraic formula ax ^ 3 + BX + 1 is 6, then when x = - 2, what is the value of the algebraic formula ax ^ 3 + BX + 1?

There are 12 boys more than two fifths of the class, and one half of the boys are girls. How many students are there in the class?
It's better to have a formula

Set Boys x girls y
Set of equations X-2 / 5 * (x + y) = 12
x=2y
We get x = 30, y = 15
x+y=45

Use factorization to calculate the square of (56 * 3 / 2) and (43 * 3 / 1)

(56 * 3 / 2) ^ 2 - (43 * 3 / 1) ^ 2
=(56*2/3+43*1/3)(56*2/3-43*1/3)
=1/3*(112+43)*[1/3*(112-43)]
=1/9*155*69
=3565/3

There are three schools: school a, School B and school C. 12% of the number of school a is equal to 13% of the number of School B and 37% of the number of school C. It is known that school C has 120 more students than school A. how many students are there in the three schools?

The number of students in school a: 120 △ 37-1, = 120 △ 76-1, = 120 △ 16, = 720; the number of students in school B: 720 × (12 △ 13), = 720 × 32, = 1080; the number of students in school C: 720 + 120 = 840; the number of students in three schools: 720 + 840 + 1080 = 2640

What is 123 + 321 + 1234567 + 7654321 + 7 + 8 + 8 + 7 + 70 + 80 + 10
10 seconds

10 seconds is impossible, go to God!