3 math problems in the first year of junior high school Addition and subtraction of rational numbers

1）.-4(a+b)+cd+x 3+(a+b-cd)x=1+x 3-x=-1 or 3

2）.0 or -2 or 2

3）.-2/1-3/2-4/3-5/4...2000/1999=-（2/1+3/2+4/3+..2000 1999) = I forgot about this, I haven't seen this for years, I'm sorry 、、、

Question 2. When a>0 and b<0, 0 is obtained

When a>0 and b<0, 0 is obtained

a>0, b>0, get 2

a>0, b>0, get 2

4a-4b-(-cd)+x/3+(a+b-cd)x0+1±1+(0-1)x(±3)

1x(±3)

Note: (-1)x3, 1x3, 1x(-3), (1)x(-3) or you see if it's right.

When a>0 and b<0, 0 is obtained

When a>0 and b<0, 0 is obtained

a>0, b>0, get 2

a>0, b>0, get 2

I agree with him on this question.

I'll think about the third question.

=Because, =So.

ab is the opposite of each other, a = the reciprocal of each other, c = 1 bx|=3, x=3, when x=3.

i.e. -4a-4b-(-cd)+x 3+(a+b-cd)x-(4a+4b)+cd+1+(0-1) 3 when x= -3.

i.e. -4a-4b-(-cd)+x 3+(a+b-cd)x-(4a+4b)+1+(-1)+(0-1) (3)a, b is a non-0 rational number, a≠0, a= a; b≠0，b=±b。

When a 0, b 0.

i.e. 丨a丨 a + b 丨b丨.

a÷a+b÷b

When a 0, b 0.

i.e. 丨a丨 a + b 丨b丨.

a÷a+（-b）÷|b|

1-b b {optional}

When a 0, b 0.

i.e. 丨a丨 a + b 丨b丨.

a|÷（a）+b÷b

a÷（-a）+1

When a 0, b 0.

i.e. 丨a丨 a + b 丨b丨.

a|÷（a）+（b）÷|b|

a÷（-a）+（b）÷b

When a 0, b 0, the value of this formula is 2; When a 0, b 0, a 0, b 0, the value of this formula is 0; When a 0, b 0, the value of this formula is 2;

1. True/False questions (1 point for each question, 4 points in total).

1 The opposite of a number must be smaller than the original. （

2.If two rational numbers are not equal, then the absolute values of these two rational numbers are also not equal. （

4.If a+b=0, then a,b are inverse numbers to each other. (

2. Multiple choice questions (1 point for each question, 6 points in total).

1 The opposite number is the number of itself which is ( ).

a. 1 b. -1 c. 0 d.does not exist.

2 In the following statement, the correct one is ( ).

a.There is no such thing as the smallest natural number bThere is no such thing as the smallest positive rational number.

c.There is the largest positive rational number dThere is a minimum negative rational number.

3 If the sum of two numbers is positive, then these two numbers ( ).

a.are all positive numbers bOne positive and one negative care all negative dAt least one is a positive number.

4. In the following formulas, the equal sign is (

a、－ =6 b、 =－6 c、－ =－1 d、 =－

5. The distance between the two points of the number 8 and 2 represented on the number line is (

a、6 b、10 c、-10 d-6

6. The absolute value of a rational number is equal to itself, and this number is (

a, positive b, non-negative c, zero d, negative.

3. Fill-in-the-blank questions (1 point per blank, 32 points in total).

1.The opposite number is 2 and the number whose absolute value is equal to 2 is

3.The largest negative integer is the smallest positive integer is

4.There are integers with an absolute value less than 5; There are negative integers with absolute values less than 6.

5.The three elements of the number line are

6.If a rise of 6 meters is recorded as 6 meters, then 8 meters is denoted .

7.The two numbers represented on the number line are always greater than the number of .

8.The opposite of 0 is 4, and the opposite of 0 is , and 4) is .

9.The smallest number with absolute value is , and the absolute value of 3 is .

11.The number represented by a point of 1 unit length on the number axis that is 1 distance from the point representing 2.

In rational numbers, the largest negative integer is , the smallest positive integer is , the smallest non-negative integer is , and the smallest non-negative number is .

12.Fill in the following numbers in the appropriate curly brackets:

6,,7,0,,200%,30,000,

Positive integer sets, negative integer sets, fraction sets, natural numbers sets, negative sets, positive sets.

4. Calculation questions (each sub-question is worth 20 points).

5. Draw the number line, and represent the following groups of numbers on the number line, and arrange them in order from large to small, and connect them with ">": (3 points for each sub-question, 6 points in total).

6. Draw the dots representing the following numbers on the number axis, and then connect the numbers with the " " sign in the order from small to large.

3, ,0, 2 (4 points).

7. Write the calculation results directly (this question has a total of 4 points, each question is worth points).

10 minus 30 plus 1/30 equals 40 and 1/30

－38）＋52＋118＋（－62）＝

5/6 + 15 and 4/5

1/7) + (2/7) + 1 and 3/7).

5 7 + [-3 8] = again

39+[-23]+0+[-16]= 0

3x+2y-5x-7y

Mixed addition, subtraction, and operation of rational numbers.

1 Calculation Questions.

2.Calculation problem: (10 5 = 50).

3x+2y-5x-7y

1) Calculation Questions:

16)4a)*(3b)*(5c)*1/6

1. a^3-2b^3+ab(2a-b)

a^3+2a^2b-2b^3-ab^2

a^2(a+2b)-b^2(2b+a)

a+2b)(a^2-b^2)

a+2b)(a+b)(a-b)

2. (x^2+y^2)^2-4y(x^2+y^2)+4y^2

x^2+y^2-2y)^2

3. (x^2+2x)^2+3(x^2+2x)+x^2+2x+3

x^2+2x)^2+4(x^2+2x)+3

x^2+2x+3)(x^2+2x+1)

x^2+2x+3)(x+1)^2

4. (a+1)(a+2)+(2a+1)(a-2)-12

a^2+3a+2+2a^2-3a-2-12

3a^2-12

3(a+2)(a-2)

5. x^2(y+z)^2-2xy(x-z)(y+z)+y^2(x-z)^2

x(y+z)-y(x-z)]^2

xz+yz)^2

z^2(x+y)^2

6. 3(a+2)^2+28(a+2)-20

3(a+2)-2][(a+2)+10]

3a+4)(a+12)

7. (a+b)^2-(b-c)^2+a^2-c^2

a+b)^2-c^2+a^2-(b-c)^2

a+b+c)(a+b-c)+(a+b-c)(a-b+c)

a+b-c)(a+b+c+a-b+c)

2(a+b-c)(a+c)

8. x(x+1)(x^2+x-1)-2

x^2+x)(x^2+x-1)-2

x^2+x)^2-(x^2+x)-2

x^2+x-2)(x^2+x+1)

x+2)(x-1)(x^2+x+1)

Did you make a mistake in the first question? None of them are right.

5/6)-

2/3 and 2/3 solution: original formula = [(-2008)-5/6]-[2007 + 2/3] + (4000 + 2/3).

A: The average 200 grams of milk powder contains 27 grams of protein.

2.There are 5 bags of not less than 28 grams, so the pass rate is 5 10 = 50% or -18

Solution: Original formula (Zhaosun -4 1 4) and Zheng Chain + (-3 1 Cong Ran 8) + (4 7 8) + (5 1 2).

Negative thirteen and one half.

(-1)+(1)+(1)+…1) +2009 (1004pcs-1).

1)+1+(-1)+1+……1) +1+(-1) (1 and 1 are added alternately to 0, and there is an extra -1 at the end).

1+1+1+……1 (50 1s).

Solution: Original formula = 1004x(-1) + 2009 = 1005

Solution: Original formula = 1000x0-1 = -1

Solution: Original = 50x1 = 50

1) Solution: original formula = 1 + (3-2) + (5-4) + (7-6)....+2007-2006）+（2009-2008）

The third step is to write or not to write.

2) Solution: original formula = (1-2) + (3 + 4) + (5-6) + (7 + 8) ....+2001-2002）

3) Solution: original formula = (-1+2) + (3+4)....+99+100) The third step can not be written.

What grade are you in?

Hope it helps you in your studies.

The distance between a point representing a and a point representing -5 because a+5 = a-(-5).

|a+5|

a-(-5)|

So is the distance between the point representing a and the point representing -5.

Launched according to the above.

a+5||a-(-5)|

So is the distance between the point representing a and the point representing -5.