6 seconds
9 seconds
3 hours
20 seconds

65 seconds
4 hours
1 minute
75 seconds

73 seconds
33 minutes
85 seconds
2 minutes

123 seconds
 hour
4 hours and  hour
 hour

 hour
50 minutes and  hour
35 minutes
 hour

1 hour 
43 minutes
35 seconds
50 seconds

1 hour and  hour
1 hour and  hour
1 hour 18 minutes
12 seconds

Bài thi số 2: Đừng để điểm rơi
Câu 1: 8 liters of oil is filled in the fisrt can; 6 liters of oil is filled in the second can. How many liters are there in each can if they are filled equally? 
Câu 2: Convert:  century = … years. 
Câu 3: Convert:  day = … hours. 
Câu 4: Convert:  day = … hours. 
Câu 5: Convert:  century = … years.  
Câu 6: Convert:  day = … hours. 
Câu 7: Convert: 2 hours = …minutes. 
Câu 8: Convert: 2kg = …g. 
Câu 9: Convert: 5kg = …g. 
Câu 10: How many 2 - digit numbers can you make by using 1; 0; 3; 4? 
Câu 11: How many 2 - digit numbers can you make by using 1; 2; 3 and 4? 
Câu 12: How many 3 - digit numbers can you make by using 1; 2; and 3? 
Câu 13: Find the arithmetic mean of consecutive numbers from 1 to 7. 
Câu 14: Find the arithmetic mean of consecutive numbers from 1 to 15. 
Câu 15: Find the arithmetic mean of consecutive numbers from 1 to 99. 
Câu 16: Find the arithmetic mean of consecutive numbers from 3 to 11. 
Câu 17: Find the arithmetic mean of consecutive numbers from 5 to 17. 
Câu 18: How many years are there in 4 centuries? 
Câu 19: If A; B and C are odd numbers such that A < B < C and A + B + C = 23 then the possible greatest value of C is… 
Câu 20: If a = 10; b = 12 and the average of a, b, c is 17 then c = … 
Câu 21: If the average of m and 9 is 14. Then m = ... 
Câu 22: If the average of three distinct numbers is 18 then the possible greatest value for one of these numbers is ... 
Câu 23: If the average of y; y + 2 and y + 4 is 12. Then y = ... 
Câu 24: The average of 51; 64 and y is 124. Then y = ... 
Câu 25: The average of the natural numbers from 9 to 21 is... 
Câu 26: There are 8 packs of cookies, each of them weighs 150g. There are also 4 packs of candies, each of them weighs 200g. How many kilograms of cookies and candies are there altogether? 
Câu 27: There are 28, 27, 32 and 37 students in 4 classses 4A, 4B, 4C and 4D respectively. What is the average number of students in each class? 
Câu 28: Write down the greatest even 3 - digit number. 
Câu 29: Write down the greatest odd 3 - digit number. 

Exam 3: Leo dốc
Câu 1: 56 + 87 = 87 + … The missing number is ... 
Câu 2: 98 + 72 = 72 + … The missing number is ... 
Câu 3: A fish weighs 1kg700g, a hundle of average weighs 300g. How many kilograms do they weigh in total? 
Câu 4: Every 2 jackets cost $30 and every 4 coats cost $40. Find the total cost of 8 such jackets and 16 such coats? 
Câu 5: Find the value of a such that: 115 x 99 = 110 x 99 + 10 x 99 - a x 99. 
Câu 6: Find the value of x such that: x - 3925 = 1527. 
Câu 7: Find the value of x such that: x - 3925 = 1559. 
Câu 8: Find the value of y, if 58 < y < 62 and y is an even number. 
.: Jenny, Mary and Anna have a total 390 stamps. Jenny has 39 stamps more than Anna and Anna has 45 stamps more than Mary. How stamps does Jenny have? 
Câu 10: If a + b = 279, a < b and there are 13 odd numbers between a and b. Then the value of a is ... 
Câu 11: In this figure, MNPQ is a square. Each its side is 15cm long. MGHQ is a rectangle and its width is 12cm shorter than its length. The perimeter of the rectangle GNPH is ...cm. 

Câu 12: The 20th century starts in 1901. It ends in … 
Câu 13: The 21st century starts in 2001. It ends in … 
Câu 14: The average of all 3 - digit even numbers is ... 
Câu 15: The average of all 4 - digit even numbers is ... 
Câu 16: The average of all even numbers that are smaller than 1000 is ... 
Câu 17: The average of five consecutive numbers is 105. Find the greatest number? 
Câu 18: The average of five numbers is 20. The average of the five numbers is 16 when one of the numbers is changed to 4. What is the original value of the changed number? 
Câu 19: The average of four numbers is 25. The average of the four numbers is 23 when one of the numbers is changed to 6. What is the original value of the changed number? 
Câu 20: The average of six numbers is 10. The average of the six numbers is 8 when one of the numbers is changed to 3. What is the original value of the changed number?
Câu 21: The difference of 10999 and the least 3 - digit number is … 
Câu 22: The difference of 10999 and the least 4 - digit number is … 
Câu 23: The greatest 3 - digit number is ... 
Câu 24: The greatest 4 - digit number is … 
Câu 25: The last digit of the product 2 x 4 x 6 x … x 78 is ... 
Câu 26: The last digit of the product 3 x 5 x 7 x 9 x 11 is ... 
Câu 27: The figure below is made up of 4 squares its perimeter is 40cm. What is the area of one square? 

 Câu 28: The sum of four consecutive natural numbers is 8054. The greatest number is…..