Thầy ơi, phần thi cấp quận bé nhà em có một bài không làm được, trong phần 12 con giáp, bài tính tuổi. Tuy nhiên đề của thầy cũng không thấy có bài này. Mà không hiểu sao hiện giờ vẫn không vào để thi tự do vòng 8 được .

nhaibt đã viết:Thầy ơi, phần thi cấp quận bé nhà em có một bài không làm được, trong phần 12 con giáp, bài tính tuổi. Tuy nhiên đề của thầy cũng không thấy có bài này. Mà không hiểu sao hiện giờ vẫn không vào để thi tự do vòng 8 được .

Mình chỉ lướt sơ qua vài lượt để lấy đề lớp 4 rồi phải quay sang lấy đề lớp 5 nên chưa lấy được hết đề lớp 4 thì chương trình đã khóa không cho thi nữa nên chưa thể làm tiếp được. Khi nào chương trình mở lại thì mình sẽ lại tiếp tục rà những đề còn sót. Tuy nhiên, bạn đừng quá quan tâm đến những bài đã qua mà hãy tập trung cho vòng tỉnh sắp tới thì hơn.

nhaibt đã viết:Nhờ thầy giảng giúp bài sau ạ:

For every camera a salesman sold, he would receive $35. For every 5 camera he sold, he would receive an extra $25. How many cameras did the salesman sell if he received $470? Answer: 12

Tạm dịch:

Giải:
Tiền thưởng khi bán được 5 máy quay phim là: 35 x 5 + 25 = 200 ($)
Tiền thưởng khi bán được 10 máy quay phim là: 200 x 2 = 400 ($)
Số máy quay phim cần phải bán thêm là: (470 - 400) : 35 = 2 (máy)
Số máy quay phim cần phải bán để được thưởng 470 đô la là: 10 + 2 = 12 (máy)

Liên đã viết:Mình chưa hiểu đề bài này
Giúp mình hiểu với!

Rosana sews 234 buttons on dresses in a day. How many buttons will she have left after 5 weeks if she has 22340 buttons at fisrt? Answer:

Tạm dịch:

Giải:
Số nút áo đầm Rosana may được sau 5 tuần làm việc là: 234 x 7 x 5 = 8190 (nút)
Số nút áo đầm cần phải may tiếp là: 22340 - 8190 = 14150 (nút)

Tái bút: Mình đã cập nhật hoàn chỉnh lời giải cho những câu hỏi của vòng 8 (vòng huyện) rồi. Các bạn có thể xem và tải toàn bộ: Đề và đáp án vòng 8 (vòng huyện) thi Toán tiếng Anh (Math ViOlympic) lớp 4 năm học 2016 - 2017 tại đây.

Các bạn có thể tải toàn bộ: Đề và đáp án ôn thi vòng 10 (cấp Quốc gia) Toán tiếng Anh (Math ViOlympic) lớp 4 NH 2016 - 2017 tại đây.

Exam 1: Cóc vàng tài ba

Giải:

Anna bought 40 jellybeans. Which statement is INCORRECT? Answer: She can divide the beans equally into three groups.

Giải:

Bob chose a natural number and multiplied it by four. Which of following numbers could not be his answer? Answer: 4846

Giải:

Donald Trump has 10 grandchidren, all of different ages. Anna is the eldest. The sum of ages grandchidren is 190. At least how old is Anna? Answer: 24

Giải:

Given five numbers, the average of two numbers is 17 and the average of the other three numbers is 12. The average of all these numbers is… Answer: 14

Giải:

In the following expression: 20 - 16 +7 : 36 x 12, if “+” means “x”; “-” means “+”; “:” means “-” and “x” means “:” then its value is… Answer: 129

Giải:

Suppose all counting numbers are arranged in column as shown at right. Under what letter will the number 2016 appear? Answer: F

Giải:

The area of the following rhombus is … Answer: 60cm²

Giải:

The value of expression: A = 1/2016 + 3/2016 + 5/2016 + ... + 2015/2016 is… Answer: 504

Giải:

Which of following numbers is smaller than 55606149 and larger than 55604896? Answer: 55605268

Giải:

Exam number 2: Fill in the blank with the suitable number

Question 1:
Fill the missing number in the blank
44444 = 40000 +400+ 4040 + 4

Question 2:
The average of 4, 8, x and 13 is 8. The value of x is 7

Giải:

Question 3:
The following chart shows the number of fruits in a shop. There are 40 more oranges than peaches.

Giải:

Question 4:
How many zero digits are there in ten million?
Answer: 7

Giải:

Question 5:
The sum of two fractions 1/2 and 1/3 is a fraction with denominator of 12. Find its numerator
Answer: 10

Giải:

Question 6:
Three pumpkins are weighed in pairs in all possible ways. The weights of all these pairs are 8kg, 9kg and 11kg. How much does the lightest pumpkin weight?
Answer: 3 kg.

Giải:

Question 7:
The floor of a rectangular room is covered with square tiles. The room is 24 tiles long and 16 tiles wide. The number of tiles in the outer border of the floor is 76

Giải:

Question 8:
It takes Jack 42 minutes to cut a long log of wood into seven pieces. How long will it take him to cut that log of wood into nine pieces?
Answer: 56 minutes.

Giải:

Question 9:
There are 3 children in a family,Jack,Mary and Peter.Mary can clean the house for 1 hour.Jack can do thesame job for 2 hours and Peter needs 6 hours. If they do the job together then they need 36 minutes.

Giải:

Question 10:
MNPQ is a square that is made up of two identical rectangles and two squares of area 9 cm² and 16 cm². The area of the square MNPQ is 49 cm².

Giải:

Exam 3: Vượt chướng ngại vật

Bài này chủ yếu là các bài toán có hình. Xin các bạn cảm phiền xem trực tiếp trong file đính kèm.

Đề và đáp án ôn thi vòng 10 (cấp Quốc gia) Toán tiếng Anh (Math ViOlympic) lớp 4 NH 2016 - 2017 đã được đăng riêng tại đây. Để người đọc khỏi mất thời gian tìm kiếm, mình xin phép được trích đăng lại.

Các bạn có thể tải toàn bộ: Đề và đáp án vòng 9 (vòng tỉnh) thi Toán tiếng Anh (Math ViOlympic) lớp 4 năm học 2016 - 2017 tại đây.

Bài thi số 1: Đừng để điểm rơi

A chair costs $989 less than the cost of 2 tables. If each table costs $689, find the total cost of a chair and 2 tables? Answer: 1767

Giải:

Find x, y such that when N =   is divided by 2; 5 and 9, the remainder is 1. Answer: x = 3 and y = 1

Giải:

Jane had 27kg of flour. She used 1/3 of it in January and 1/3 of the rest in February. How many kilograms of flour did she have left? Answer: 12

Giải:

Mr Tom drove from his apartment to his office which is 1243m away. What is the total distance travelled to and fro by him in 4 days? Answer: 9.944 (km)

Chú ý:

What is the missing number in the blank? 38765 - 4562 = … - 8720. Answer: 42923

Giải:

Which of the following fractions is the greatest? (7/12, 8/15, 17/30, 1/2). Answer: 7/12


Which of the following fractions is the smallest? Answer: 1/2


Which of the following is the smaller than 1/2? Answer: 7/15


Write >; <; = in the blank: 1818/2121 ... 7272/7373. Answer: <

Giải:

Which of the following calculations equals 5/36? Answer: 1/9 + 5/12 - 7/18

Giải:

Bài thi số 2: 12 con giáp

3 shirts cost as much as 5 blouses. Mr Tom bought 2 such shirts and 4 such blouses for $ 110. Find the cost of 6 such shirts? Answer: 150

Giải:

A rectangular field is 48m long and 36m wide. Find the cost of turfing with grass at $15 per m² to cover the whole field. Answer: 25920

Giải:

A school has 24 classes and there are 40 students in each class. 1/8 of students wear glasses and 1/12 of those who wear glasses are boys. How many schoolgirls wear glasses in the school? Answer: 110

Giải:

Anna’s salary is $3650. She spends $2760 every month and saves the rest. How much will she save in 9 months? Answer: 8010

Giải:

Brenda earns $840 more than Kenneth. Last week, Brenda spent $480 while Kenneth spent 1/3 of his salary and he had $1350 left. How much money did Brenda have left? Answer: 2385

Giải:

David wanted to buy 6 shirts but he was short of $21. He bought 4 shirts instead of 6 shirts and had $3 left. How much money did he have at first? Answer: 51

Giải:

Harry spent 1/4 of his money on a book. He then spent 1/2 of the money left on a watch. If he had $27 left, how much money did he have at first? Answer: 72

Giải:

Mary went shopping with $1060. She bought 56 pens at $16 each. How much mony did she have left? Answer: 164

Giải:

Simon travelled 1280km more than John. Ben travelled 1120km more than Simon. The three men travelled 6674km. What is the distance travelled by Simon? Answer: 2278

Giải:

There are 84 apples in a box. 3/4 of them are red apples. The rest are green apples. How many green apples are there in the box? Answer: 21

Giải:

Tom and Jacob had the same number of tarts to sell. Tom sold 78 tarts and Jacob sold 240 tarts. Tom found that the number of tarts he had left that was thrice as the number of tarts Jacob had left. How many tarts did Tom have at first? Answer: 321

Giải:

Vì là 12 con giáp nên có lẽ là còn 1 câu hỏi nữa (câu hỏi khi bấm chuột vào con heo) nhưng vì lỗi chương trình nên mình không biết nó là như thế nào. Mình đã cố gắng thử thi lại nhiều lần nhưng vẫn chưa thấy hiển thị nội dung câu hỏi. Khi nào hết lỗi, mình sẽ cập nhật lại.


Bài thi số 3: Web tự luận

Câu 1:
The perimeter of a rectangle is 44cm. The length is 12cm. Find the width of the rectangle.
Answer: The width of the rectangle is 10 cm.

Giải:

Câu 2:
Richard gave 1/4 of his money to his mother and spent 80 dollars on food. He then had 94 dollars left. How much money did he have at first?
Answer: He had 232 dollars at first.

Giải:

Câu 3:
The product of 2 different natural numbers is 9. Their sum is 10

Giải:

Câu 4:
Find the missing number in the numbers pattern.
1, 2, 6, 24, 120, ..., 5040
Answer: The missing number is 720

Giải:

Câu 5:
1/4 of Benard's money is equal to 1/8 of Joanne's money. If Joanne has 384 dollars, how much money does Benard have?
Answer: Benard has 192 dollars.

Giải:

Câu 6:
5/12 of the dresses in a shop are blue. There are 384 pink dresses. If 1/3 of the dresses are black, how many dresses are there in the shop?
Answer: There are 1536 dresses in the shop.

Giải:

Câu 7:
Tom bought 30 similar books at 26 dollars each. If he had bought 8 similar electronic calculators with the same amount of money, he would be short of 12 dollars. What is the cost of an electronic calculator?
Answer: The cost of an electronic calculator is 99 dollars.

Giải:

Câu 8:
If x is a natural number and 7/9 < x/12 then the smallest value of x is 10

Giải:

Câu 9:
Gabriel and Tom went shopping with the same amount of money. After Gabriel spent 86 dollars and Tom spent 426 dollars, the rest money of Tom is  the rest money of Gabriel. How much money does Tom have left?
Answer: Tom has left 85 dollars.

Giải:

Câu 10:
Let A = 8910111213... (A is wrote by the consecutive natural numbers).
If A has 178 digits then when A is divided by 5 the remainder is 2

Giải:

Đề và đáp án vòng 10 (vòng quốc gia) thi Toán tiếng Anh (Math ViOlympic) lớp 4 năm học 2016 - 2017

Bài thi số 1: Đập dế

A meeting room can hold 989 people. How many people can 98 such meeting room hold? Answer: 96922

Giải:

30 trees are equally spaced along one side of a straight road. The distance from the first tree to the thirteen tree is 312m. What is the distance in meter between the first and last tree? Answer: 754

Giải:

Nick ate 1/5 of a cake. Emma ate 1/3 of what was left. What fraction on the cake is left uneaten? Answer: 8/15

Giải:

How many minutes are there in 7/12 hour and 360 seconds? Answer: 41

Giải:

Anna wrotea sequence of numbers using the rule “subtract 8”. The first two terms in her sequence were 2017 and 1999. Which number below is one term of Anna’s sequence? Answer: 1833

Giải:

Calculate: 5 x (1/5 + 1/17) - (2/5 + 2/17 + 6/10 + 9/51) = ... Answer: 0

Giải:

Which two shapes could be put together to form the rectangle beside? Answer: Hình D (Hình ngoài cùng bên phải)

Giải:

If A * B means (A + 2 x B) : 2, then (44 * 24) * 48 is … Answer: 71

Giải:

A and B are sibling but of different genders. A has an even number of brothers and an even number of sisters. (Zero does not count). B has an odd number of brothers and an odd number of sisters. What is the minimum number of children in this family? Answer: 5

Giải:

The total weight of several stones is 707 kilograms. The lightest five stones weigh 180 kilograms. The heaviest six stones weigh 234 kilograms. The weights of stones are distinct and are not nescessarily whole numbers. The number of stones is … Answer: 19

Giải:

Bài thi số 2: Web tự luận

Câu 1:
The quotient of two numbers is one fifth of the bigger number and four times the smaller one. What is the quotient?
Answer: 20

Giải:

Câu 2:
Jack is ranked 7^th  in his class from top and 21^th from bottom. How many students are there in Jack’s class?
Answer: There are 27 students.

Giải:

Câu 3:
The perimeter of the parallelogram ABCD is 48m. The height corresponding to the base CD is 7m and the side AD is 9m. Find the area of the parallelogram.
Answer: The area is 105 m².

Giải:

Câu 4:
Mr. Trump buys 71 pencils. Each pencil costs 2 dollars, and 67 pens, each pen costs 3 dollars. He gets a discount of 1 dollar for 3 pencils he buys and a discount of 2 dollars for 5 pens he buys. How much in total does he pay?
Answer: 294 dollars.

Giải:

Câu 5:
Thirteen friends join a sport club together. Eight of them play football, six of them play tennis and five of them play badminton. If everyone plays sport but no one plays only two kinds of sport, how many people play all three kinds?
Answer: 3

Giải:

Câu 6:
James has 2 more chickens than dogs. One half the chicken legs are equal to three eighths the dog legs. How many legs are there in total?
Answer: 28 legs.

Giải:

Câu 7:
Two of my digits are odd, but my unit digit is even. The sum of my digits is 14. I’m between 567 and 599 and I' m not 590. What number am I?
Answer: 572

Giải:

Câu 8:
The average of 17 distinct whole numbers is 17.What is the largest possible value of these numbers?
Answer: 169

Giải:

Câu 9:
Alice said to her mother, “If I reverse the two digits of my age, I will get your age”. Her mother said, “Tomorrow is my birthday, and my age will then be three times yours”. It is known that their birthdays are not on the same day. How old is Alice?
Answer: 14 years old.

Giải:

Câu 10:
Forty students from five grades brought 50 candies for the “Trick or Treat” game in a Halloween party. It is known that students from the same grade brought an equal number of candies, while students from different grades brought different numbers of candies. How many students brought exactly one candy?
Answer: 36 student(s)

Giải:

Bài thi số 3: Đừng để điểm rơi

Emily orders one food and one drink from the menu. How many different ways can she order? Answer: 25

Giải:

Find the sum of all 2 - digit numbers such that each number is 13 times its tens digit. The sum is … Answer: 78

Giải:

A boy weighed his twin cats and two identical hats together an got 2200g. He then weighed one hat and a 10kg - weight and got 10450g. The weight of one cat was … g. Answer: 650

Giải:

If the product of two whole numbers X and Y is 64, what is the maximum sum of X and Y? Answer: 65

Giải:

Using each of the digits 1, 2, 3, 4 and 5 exactly once to form 5 - digit numbers. How many are divisible by 12? Answer: 24

Giải:

Anna, Brat and Cindy had $635 altogether. Anna spent   of her money and Brat spent thrice the amount Anna spent. Cindy spent $50. If they had the same amount of money left, how many dollars did Anna have at first? Answer: 180

Giải:

Oranges are sold in baskets of three at the cost of $4 each, or baskets of five at the cost of $5 each. What is the smallest cost at which John can buy 158 oranges? Answer: 159

Giải:

The figure below is made up of four identical squares and one rectangle. If the perimeter of the figure is 64cm and the perimeter of the rectangle is 16cm, then the area of each square is … cm². Answer: 36

Giải:

How many 4 - digit numbers contain the digit 2, or the digit 3 or both? Answer: 5416

Giải:

Ten numbers were written on 10 cards as follows:

0

1

2

3

4

5

6

7

8

9

Mr. Zack chose 4 of these cards to form 4 - digit odd number. He stood front of a mirror and looked at it up - side - down through the mirror. He saw a new number. If the new number was 720 larger than the orginal one, then the orginal number is … Answer: 6089

Giải:

Thầy ơi, cho em hỏi bài này với ạ!!!
Some men meet at a conference. Each man shakes hands with each other exactly once. If there are 4950 handshakes in total then the number of men is ...
Em cảm ơn thầy nhiều ạ!!

hanghyun đã viết:Thầy ơi, cho em hỏi bài này với ạ!!!
Some men meet at a conference. Each man shakes hands with each other exactly once. If there are 4950 handshakes in total then the number of men is ...
Em cảm ơn thầy nhiều ạ!!

Tạm dịch:

Với n là số người thì công thức tính cái bắt tay là: n(n - 1) : 2
Theo đề bài ra ta có:
n(n - 1) : 2 = 4950
n(n - 1) = 4950 x 2
n(n - 1) = 9900
n(n - 1) = 100 x 99
n = 100
Vậy: Tổng số người đàn ông tham gia hội nghị là 100 người