To transport 29.5 tons of coal, a 4-ton truck should be used for three times, and the rest should be transported by a 2.5-ton truck. How many times will it take to complete the transportation?

To transport 29.5 tons of coal, a 4-ton truck should be used for three times, and the rest should be transported by a 2.5-ton truck. How many times will it take to complete the transportation?

The tonnage of the first three times: 4 × 3 = 12 (tons), the remaining tonnage: 29.5-12 = 17.5 (tons), the number of times to be transported: 17.5 △ 2.5 = 7 (Times); the comprehensive formula: (29.5-4 × 3) △ 2.5, = 17.5 △ 2.5, = 7 (Times); a: it will take 7 times to complete the transportation
Students go to spring outing and divide 42 bottles of mineral water and 30 bottles of coke equally into several groups. After that, how many groups can they be divided at most? How many bottles of each of the two drinks are given to each group?
The factors of 42 are: 1, 2, 3, 6, 7, 14, 21, 42. The factors of 30 are: 1, 2, 3, 5, 6, 10, 15, 30. The greatest common factors of 42 and 30 are: 6.42 △ 6 = 7 (bottles), 30 △ 6 = 5 (bottles)
Mixed operation of mathematical rational numbers
-3-3 × (1 / 3-1 / 2) equals ()
A 5 / 6 B - 2 and 1 / 2 C - 4 and 2 / 3 D - 1 and 1 / 3
The third power of 1-2 × (- 3) is equal to ()
A -27 B -23 C 21 D 25
21-1 / 6 =? If 1 / 3 of the sum of four rational numbers is 4, and three of them are - 12, - 6, 9, then the fourth number is ()
A -9 B 15 C -18 D 21
Given an equation: () / () [] () / () fill in two positive numbers and two negative numbers whose absolute values are 1,2,3,4 in four brackets, and fill in one four operation symbols in the brackets to minimize the operation result
【【【【【【【【21 - 1/6 = 】】】】】】】】】】
﹙1﹚B
﹙2﹚D
﹙3﹚D
﹙4﹚0.000000000000000000000000000000000000000000000000000000000000001÷1×-1÷0.999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
【【【【【【【【21 - 1/6 = 】】】】】】】】】】=20 5/6
BDD-1   4   *   -2     3
What a simple feeling --
To transport 29.5 tons of coal, a truck with a load of 4 tons is used to transport the coal three times, and the rest is transported by a truck with a weight of 2.5 tons, and x times is needed
The students went on a picnic and divided 42 bottles of mineral water and 30 bottles of coke equally among several groups, just finished. How many can they be divided at most
42=7*3*2
30=5*3*2
The greatest common divisor is 6,
It can be divided into up to six groups
It can be divided into six groups (using short division). Mineral water: 42 △ 6 = 7 (bottle) coke: 30 △ 6 = 5 (bottle)
Mixed operation of rational numbers
1.（-1/2)+（+3/5）-3/2
2. - 4.2 divided by 7 / 8 times (- 5 / 4)
3. The cube of (1 / 3-1 / 2) - 2 multiplied by the square of (- 6)
Of the following groups, the reciprocal is ()
A-0.125 and 1 / 8
B-0.5 and 2
C-1 and 2
D minus one and a quarter and minus 4 / 5
1.（-1/2)+（+3/5）-3/2=-(7/5)
2. - 4.2 divided by 7 / 8 times (- 5 / 4) = 6
3. The cube of (1 / 3-1 / 2) - 2 multiplied by the square of (- 6) = - 14
The reciprocal of the following groups is (d)
A-0.125 and 1 / 8
B-0.5 and 2
C-1 and 2
D minus one and a quarter and minus 4 / 5
You should choose D
1、 (-7/5)
2、 6
3、 -14
4. Choose D
-7/5 6 4 D
To transport 29.5 tons of coal, a 4-ton truck should be used for three times, and the rest should be transported by a 2.5-ton truck. How many times will it take to complete the transportation?
The tonnage of the first three times: 4 × 3 = 12 (tons), the remaining tonnage: 29.5-12 = 17.5 (tons), the number of times to be transported: 17.5 △ 2.5 = 7 (Times); the comprehensive formula: (29.5-4 × 3) △ 2.5, = 17.5 △ 2.5, = 7 (Times); a: it will take 7 times to complete the transportation
Students go to spring outing and divide 42 bottles of mineral water and 30 bottles of coke equally into several groups. After that, how many groups can they be divided at most? How many bottles of each of the two drinks are given to each group?
The factors of 42 are: 1, 2, 3, 6, 7, 14, 21, 42. The factors of 30 are: 1, 2, 3, 5, 6, 10, 15, 30. The greatest common factors of 42 and 30 are: 6.42 △ 6 = 7 (bottles), 30 △ 6 = 5 (bottles)
Find 7 mixed operation problems of rational numbers
Addition, subtraction, multiplication, division, power mixed operation, the best long point!
[-|98|+76+(-87)]*23[56+(-75)-(7)]-(8+4+3)
5+21*8/2-6-59
68/21-8-11*8+61
-2/9-7/9-56
4.6-(-3/4+1.6-4-3/4)
1/2+3+5/6-7/12
[2/3-4-1/4*(-0.4)]/1/3+2
22+(-4)+(-2)+4*3
-2*8-8*1/2+8/1/8
(2/3+1/2)/(-1/12)*(-12)
(-28)/(-6+4)+(-1)
2/(-2)+0/7-(-8)*(-2)
(1/4-5/6+1/3+2/3)/1/2
18-6/(-3)*(-2)
(5+3/8*8/30/(-2)-3
(-84)/2*(-3)/(-6)
1/2*(-4/15)/2/3
-3x+2y-5x-7y
Mixed operation of addition and subtraction of rational numbers
[[simultaneous practice]
1. Multiple choice questions:
(1) Write - 2 - (+ 3) - (- 5) + (- 4) + (+ 3) in the form of omitting the sum of brackets
A．-2-3-5-4+3 B．-2+3+5-4+3
C．-2-3+5-4+3 D．-2-3-5+4+3
(2) The correct result of (- 5) - (+ 3) + (- 9) - (- 7) + is ()
A．-10 B．-9 C．8 D．-23
(3) The algebraic sums of - 7, - 12, + 2 are smaller than the sum of their absolute values ()
A．-38 B．-4 C．4 D．38
(4) If + (B + 3) 2 = 0, then the value of B-A - is ()
A．-4 B．-2 C．-1 D．1
(5) The following statement is correct ()
A. Subtracting two negative numbers is equal to subtracting the absolute value
B. The difference between two negative numbers must be greater than zero
C. Positive minus negative is actually the algebraic sum of two positive numbers
D. Negative minus positive equals the absolute value of negative plus positive
(6) Formula - 3-5 cannot be read as ()
A. The difference between - 3 and 5 B. the sum of - 3 and - 5
C. The difference between - 3 and - 5 d. - 3 minus 5
2. Fill in the blanks: (4 ′× 4 = 16 ′)
（1）-4+7-9=- - + ；
（2）6-11+4+2=- + - + ；
（3）（-5）+（+8）-（+2）-（-3）= + - + ；
（4）5-（-3 ）-（+7）-2 =5+ - - + - .
3. Write the following forms in the form of sum with brackets omitted, and give two ways to read them: (8 ′× 2 = 16 ′)
（1）（-21）+（+16）-（-13）-（+7）+（-6）；
（2）-2 -（- ）+（-0.5）+(+2)-(+ )-2.
4. Calculation (6 ′× 4 = 24 ′)
(1)-1+2-3+4-5+6-7;
(2)-50-28+(-24)-(-22);
(3)-19.8-(-20.3)-(+20.2)-10.8;
(4)0.25- +(-1 )-(+3 ).
5. When x = - 3.7, y = - 1.8, z = - 1.5, find the value of the following algebraic formula (5 ′× 4 = 20 ′)
(1)x+y-z; (2)-x-y+z; (3)-x+y+z; (4)x-y-z.
[quality optimization training]
(1) (-7)-(+5)+(+3)-(-9)=-7 5 3 9;
(2)-(+2 )-(-1 )-(+3 )+(- )
=( 2 )+( 1 )+( 3 )+( );
(3)-14 5 (-3)=-12;
(4)-12 (-7) (-5) (-6)=-16;
(5)b-a-(+c)+(-d)= a b c d;
2. When x =, y = - and z = - the values of the following algebraic expressions are obtained respectively;
(1)x-(-y)+(-z); (2)x+(-y)-(+z);
(3)-(-x)-y+z; (4)-x-(-y)+z.
3. Verify the equation for the following three groups of numbers:
Whether a - (B-C + D) = A-B + C-D holds
(1)a=-2,b=-1,c=3,d=5;
(2)a=23 ,b=-8,c=-1 ,d=1 .
4. Calculation
(1)-1-23.33-(+76.76);
(2)1-2*2*2*2;
(3)(-6-24.3)-(-12+9.1)+(0-2.1);
(4)-1+8-7
[practical application in daily life]
On the first day, a water conservancy survey team walked 5 kilometers upstream, 5 kilometers upstream on the second day, 4 kilometers downstream on the third day, and 4.5 kilometers downstream on the fourth day. Where is the starting point of the survey team? How many kilometers apart?
Reference answer:
[synchronized practice]
1.(1)C;(2)B;(3)D;(4)A;(5)C;(6)C 2.(1)4,(-7),(-9) (2)(-6),(-11),(-4),2; (3)-5,8,2,3; (4)3,7,2;
(2.4) - 3.5; (4) - 30
5.(1)-4; (2)4; (3)0.4; (4)-0.4.
[quality optimization training]
1.(1)-,+,+; (2)-,+,-,-; (3)+,+; (4)-,+,+; (5)-,+,-,-.
2.(1) (2) (3) (4)-
3. (1) (2) all hold water
4.(1)-
(2)
(3)-29.5
(4) Note that numbers with the same sign and numbers opposite to each other should be combined first
[practical application in daily life]
1. 1 km upstream
5+5+5+5-(1-1)
29 tons of vegetables are transported to the city by trucks with a load of 5 tons and 3 tons. Each truck is just full, so each truck is loaded
Formula
4 cars of 5 tons, 3 cars of 3 tons