Tisch
A, B, C and D won the top four in a game. It is known that D is not ranked, but higher than B and C, and C is not ranked higher than B. Q: Where are they? Answer and analysis:
D is not ranked, but it is higher than B and C, so it ranks second, and A ranks 1. C is not ranked higher than B, so B is the third and C is the fourth.
The sum of two numbers is 20 16, and the number of digits of an addend is 0. If you remove this 0, it is exactly twice the other addend. What are two addends?
Answer and analysis: These two addends are: 96 and 1920 respectively. Because the "0" on the first addend has been removed, it is twice that of the second addend, so the first addend is 20 times that of the second addend. If the second addend is regarded as a multiple of 1, then the second addend is a multiple of 20, and the sum of these two numbers is 20 16, which is "65438". According to the correspondence between "quantity" and "times", the second addend can be obtained first. The two addends are: 20 10/( 1+20)=96, 20 16-96= 1920.
There are 45 people in a class. First four people stand in a row, and finally not enough people stand in a row. * * * How many rows do I need to stand?
Answer and analysis:
If four people stand in a row, then 40 people stand in 10 row * *, 44 people stand in 1 1 row, and the rest stand alone in a row, so * * needs to stand in1=10.
How is it easier?
( 1)45×9; (2)457×99; (3)762×999; (4)34×98.
Answer and analysis:
( 1)45×9=45× 10-45=450-45=405
(2)457×99=457× 100-457=45700-457=45243
(3)762×999=762× 1000-762=762000-762=76 1238
(4)34×98=34× 100-34×2=3400-68=3332
extreme
1. There are a group of soldiers in a phalanx, and there are 240 people in the outermost week. How many people are there in this phalanx? 2. Young Pioneers of a school can be arranged in a four-story hollow square. If there are 20 students on each side of the outermost layer, how many students are there in the innermost week of this hollow square? How many students are there in this four-story hollow square?
On the eve of Children's Day, around the campus sculpture, 204 pots of flowers were used to form a square with three layers on each side.
4. The students in Grade Three 1 Class participate in gymnastics performance, and the formation is exactly a regular hexagon composed of six triangles, with every seven people as one side. How many students are there in a regular hexagon? How many people participated in the gymnastics performance in Class 3 (1)?
5. The latest third-grade Olympic math problem and answer: phalanx problem: The existing pine and cypress trees are planted in a phalanx of 9 rows and 9 columns by alternating trees. How many pines and cypresses are there on the outermost layer of this square? How many pines and cypresses are there in the square?
Answer:
(1)(240÷4)- 1=59 (person) 59×59=348 1 (person)
(2)(20-2×3- 1)×4 = 42(20-40×4×4 = 256(a)
(3) Number of people on each side of the outermost layer = total number of people ÷4÷ number of layers+number of layers
204/4/3+3 = 20 (basin)
(4)7×6-6=36 people 7× 12-6×2-5=67 people.
(5) The outmost conifer is (9- 1)×4÷2= 16 (tree).
* * * There are conifers and cypresses: (9×9+ 1)÷2=4 1 (tree) 8 1-4 1=40 (tree).
A: There are 465,438+0 cypresses and 40 pines, or 465,438+0 pines and 40 cypresses.
Tisso
1.Class A has 80 more books than Class B, and Class A has three times as many books as Class B. How many books are there in Class A and Class B respectively?
Answer: The number of B-type books: 80÷(3- 1)=40 (books).
Class A copies: 40×3= 120 (copies)
2. Sum times question
The sum of two numbers is 682, and one addend is the single digit 0. If you delete 0, it will be the same as another addend. What are these two numbers?
Answer:
682÷( 10+ 1)=62
62× 10=620
A three-digit number has three times as many units as the hundredth digit, and the tenth digit has twice as many units as the hundredth digit. What are the possible numbers?
Answer and analysis:
If the hundredth bit is 1, the number in the unit bit is three times that of the hundredth bit, and the unit bit is 3; The tenth digit is twice that of the hundredth digit, and the tenth digit is 2, which is 123.
If one percent is 2, the number in the unit is 3 times that of one percent, and the unit is 6; The number in the tenth place is twice that in the hundredth place, and the number in the tenth place is 4, which is 246.
If one percent is 3, the number in the unit is 3 times that of one percent, and the unit is 9; The number in the tenth place is twice that in the hundredth place, and the number in the tenth place is 6, which is 369.
There are three such numbers, namely123,246,369.