300 questions about integral in mathematics calculation of grade one in junior high school

300 questions about integral in mathematics calculation of grade one in junior high school

1. In order to make the polynomial MX ^ 3-2x ^ 2 + 3x-4x ^ 3 + 5x ^ 2-nx about X not contain cubic and primary terms, then M + n =?
2. Given A-B = - 6, what is 3 - (B-A) = and what is 8-6a + 6B?
3. If a polynomial m subtracts - 3x + 5 to get 5x ^ 2-3x-1, then what is m equal to?
4. Given a = x ^ 3-2x ^ 2 + 1, B = 3x ^ 2-4x-3 / 2. Find (1) 3A + 2B; (2) - 2a-b
5. It is known that a is a polynomial. When calculating a - (2x ^ 2 + 5x-3), a student wrote "a -" as "a +", and the result is - x ^ 2 + 3x-7. What is the original formula? What is the correct result?
6. There are a seats in the first row of the cinema. There is no more seat in the back row than in the front row. How many seats are there in the n row of the cinema
answer:
1. First of all, we need to know what is a cubic term and a primary term. MX ^ 3, - 4x ^ 3 is a cubic term, NX, 3x is a primary term. According to the requirements of the topic, if there is no cubic term and a primary term, then M-4 = 0, M = 4, 3-N = 0, n = 3, then M + n = 7
2. (1) the idea of this problem is to change the operation symbol, 3 - (B-A) to 3 - (- A + b), and then to 3 + A-B, substituting the known A-B = - 6, so 3 - (B-A) = - 3
(2) The reason is the same as that in the previous question. Sort out 8-6a + 6B to get 8-6 (a-b), and substitute the known A-B = - 6, so 8-6a + 6B = 44
3. Since a polynomial m minus - 3x + 5, we get 5x ^ 2-3x-1, then 5x ^ 2-3x-1 + (- 3x + 5) = m, so m = 5x ^ 2-6x + 4
4. This problem can only be calculated hard. Remember to mark similar items in the same way in the process of calculation
（1）3A+2B=3X^3-8X
（2）-2A-B =-2X^3+X^2+4X-1/2
5. The idea of this problem is to find a first, a + (2x ^ 2 + 5x-3) = - x ^ 2 + 3x-7, a = - 3x ^ 2-2x-4, and then substitute a into a - (2x ^ 2 + 5x-3) to get - 5x ^ 2-7x-1
6. According to the meaning of the title, the following table should be listed:
1：A
2：A+1
3：A+2
.
.
.
N：A+N-1
The result is a + n-1

Please write the following formula in the form of (a + b) (a-b)
（1）（-a+b+c+d）(-a-b+c+d)
(2) (a+b-c)(a-b+c)
calculation
16+a-{8a-[a-9-(3-6a)]}

(1) the original formula = [(c + D-A) + b] [(c + D-A) - b]
(2) the original formula = [a + (B-C)] [a - (B-C)]
16+a-{8a-[a-9-(3-6a)]}
=16+a-{8a-[a-9-3+6a]}
=16+a-{8a-[7a-12]}
=16+a-{8a-7a+12}
=16+a-{a+12]
=16+a-a-12
=16-12
=4

It is known that the polynomial 6mx2 + 4nxy + 2x + 2xy-x2 + 10y-5 contains no quadratic term,
Find the value of - 3 / 5m-2 / 5n-10

6m-1=0 m=1/6
4n+2=0 n=-1/2

Find 10 simple calculation problems,

5 (x + y) - 5 (5 + b) × a when a = 5 / 7. 3. 62g + 62 (G + b) - B when g = 5 / 7, B = 16. 4. 3 (x + y) - 5 (4 + x) + 2Y when x = 9, y = 2. 5. (x + y) (X-Y) when x = 0.45, y = 0.65

How to calculate the multiplication of two digits, for example, 22 × 23
Checking calculation by vertical method

22
*23
--------
sixty-six
forty-four
------
five hundred and six

Is there any way to simply calculate two digit multiplication? For example, 52 * 43

You and I want to go together. I had this idea when I was in primary school (why division can be calculated orally, multiplication can't be done). Just a moment, I'll take a picture with my camera for you

When calculating the multiplication of two digits, how many digits will it take to multiply the number in one digit by another?

In the calculation of two digit multiplication, the number on one bit of one factor is used to multiply another factor. If the number on one bit of this factor is 0, 0 is obtained;

When calculating a two digit multiplication, Xiaoqin regards "7" on one digit of a factor as "1", and the result is 3726; Xiaolin regards "8" on ten digits of the same factor as "5", and the result is 2622, and the correct product should be______ ．

(3726-2622) / (81-57) = 1104 / 24 = 46, 87 × 46 = 4002. A: the correct product should be 4002

In the calculation of two digit multiplication, the bits of the first factor 25 are regarded as 8, and the result is 81 more than the correct product. What is the correct result?

If you take 25 as 28, it's three times larger than the original number
81÷3=27
25×27=675
The correct result is 675

Which is the fastest way to do mental arithmetic,

"Fast mental arithmetic", children do not have to play abacus, do not break fingers, also do not spend a long time, as long as after more than ten days, one and a half hours a day fast mental arithmetic learning, learning effect is far more than a few years of abacus mental arithmetic learning effect