1. calculation.
(1) The sum of numbers A and B plus number A is 220, and number B is 170. Find the sum of numbers a and B.
(2) When calculating the division with the remainder, Xiao Ming mistyped the dividend 1 15 as 15 1, and the quotient of the result was 3 larger than the correct result, but the remainder was exactly the same. Write this division formula.
2. Fill in the blanks.
(1) Fill in the appropriate numbers in the following () so that the average of the three numbers is 140.
( ),( )8,( )27
(2) Fill in the numbers 5, 20, 45, 80, 125, _ _ _ _ _ _ _ _ _, 245.
3. Each layer of the ladder diagram consists of black and white squares, and both ends of each layer are black squares (as shown in the figure). What is the number of white squares on the 2000th floor?
4. In a parking lot, 48 cars and motorcycles were parked, including 4 wheels for each car and 3 wheels for each motorcycle. These cars have 65,438+072 wheels. Q: How many cars are there in the parking lot?
5. Give 100 apples to 10 children, and the number of apples per child is different. The child who gets the most apples will get at least a few apples.
6. The bookshelf has three floors, A, B and C, and there are 192 books in it. First, take out as many books as B from A and put them in B, then take out as many books as C from B and put them in C. Finally, take out as many books as A from C and put them in A. At this time, there are as many books in A, B and C.
7. There are 10 chicken farms in a township, and the number of chickens in each chicken farm is different, ranging from 1 10,000. Coincidentally, the sum of the numbers of each chicken farm is equal to 34. How many chickens are raised in this 10 chicken farm?
8. What is the first number on the left of line 100 in the table below?
5 4 3 2
6 7 8 9
13 12 1 1 10
14 15 16 17
2 1 20 19 18
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9. Two children walk against the escalator. Boys can walk three steps per second and girls can walk two steps per second. As a result, from one end of the escalator to the other, the boy walked for 65,438+000 seconds and the girl walked for 300 seconds. How many levels are there in the escalator?
10. There is a five-digit odd number. All two in this five-digit odd number become five, and all five also become two, and the other numbers remain unchanged, thus obtaining a new five-digit number. If half of the new five digits are larger than the original five digits 1, what is the original five digits?
The answer to the first question
1.( 1) The sum of numbers A and B plus the number A is 220, and the number B is 170. Find the sum of numbers a and B.
According to the meaning of the question
2 A +2 B =220 ( 1)
A +2 B = 170 (2)
(1) Formula +(2)
3 A +3 B =390
Therefore, the sum of numbers a and b is
390÷3= 130
(2) When calculating the division with the remainder, Xiao Ming mistyped the dividend 1 15 as 15 1, and the quotient of the result was 3 larger than the correct result, but the remainder was exactly the same. Write this division formula.
Because the quotient is increased by 3, the divisor can be found.
( 15 1- 1 15)÷3=36÷3
= 12
Therefore, the required division type is:
1 15÷ 12=9……7
(1) Fill in the appropriate numbers in the following () so that the average of the three numbers is 140.
(5),(8)8,(3)27
The average value of three numbers is 140, so the sum of three numbers:
140×3=420
The third number should be 327.
420-327=93
Obviously, the first number is 5 and the second number is 88.
(2) Fill in the figures according to the law
5,20,45,80, 125, 180,245.
20=5+ 15
45=20+25
80=45+35
125=80+45
So the next number should be:
125+55= 180
3. Each layer of the ladder diagram consists of black and white squares, and both ends of each layer are black squares (as shown in the figure). What is the number of white squares on the 2000th floor?
According to the graph, the number of white squares on each floor is equal to the number of floors minus 1, so there should be 1999 white squares on the 2000th floor.
4. In a parking lot, 48 cars and motorcycles were parked, including 4 wheels for each car and 3 wheels for each motorcycle. These cars have 65,438+072 wheels. Q: How many cars are there in the parking lot?
Suppose 48 cars are all cars.
The number of wheels should be
48×4= 192
Therefore, the number of motorcycles is
(48×4- 172)÷(4- 1)
=20 (vehicles)
There are 48-20=28 cars.
5. Give 100 apples to 10 children, and the number of apples per child is different. The child who gets the most apples will get at least a few apples.
Everyone's number of apples should be as close as possible. 10 The child gets 1, 2,3 3... 10/0 apples, and the remaining apples are divided by 10.
[ 100-( 1+2+3+……+ 10)]÷ 10
=45÷ 10=4……5
Therefore, each child adds four more apples, and the last five children add 1 apple each. 10 The number of apples for children should be:
5,6,7,8,9, 1 1, 12, 13, 14, 15.
So the children who get the most apples are at least 15.
6. The bookshelf has three floors, A, B and C, and there are 192 books in it. First, take out as many books as B from A and put them in B, then take out as many books as C from B and put them in C. Finally, take out as many books as A from C and put them in A. At this time, there are as many books in A, B and C.
List, using backward method (bottom-up)
first
second
The third/third in ten days' work
Initial state
88
Fifty-six
48
After giving a to B.
32
1 12
48
After b is given to C.
32
64
96
After giving c to a
64
64
64
The original works of Grade A, B and C are 88, 56 and 48 respectively.
7. There are 10 chicken farms in a township, and the number of chickens in each chicken farm is different, ranging from 1 10,000. Coincidentally, the sum of the numbers of each chicken farm is equal to 34. How many chickens are raised in this 10 chicken farm?
The sum of all digits is 34, and the number less than 10000 can only be four digits.
Therefore, the number of chickens raised in each chicken farm is a four-digit number that can only be composed of 9, 9, 9, 7 or 9, 9, 8 and 8. According to the meaning of the question, the number of 10 is:
7997,9799,9979,9997,8899,8989,8998,9889,9898,9988.
Their total is: 94435 (only).