Câu 1:
A is a set of multiples of 12 less than 12. How many elements does the set A have?
Answer: The set A has  element(s)

Câu 2:
Find the remainder when  is divided by 9.
Answer: The remainder is 

Câu 3:
Find the remainder of  when it is divided by 3.
Answer: The remainder is 

Câu 4:
A is the set of factor of 12 more than 6. How many elements does the set A have?
Answer: The set A has  element(s)

Câu 5:
Find the natural number  so that the product of  and 5 is a prime number.
Answer: 

Câu 6:
Given that . How many divisors does the number A have?
Answer: The number A has  divisors.

Câu 7:
Given that . How many divisors does the number A have?
Answer: The number A has  divisors.

Câu 8:
How many prime numbers less than 10 are there?
Answer: There are  numbers. 

Câu 9:
Find the greatest 2-digit number that has 12 divisors.
Answer: It is 

Câu 10:
Among all natural number pairs  satisfy , one pair has the greatest product. What is this product?
Answer: The greatest product is 

Question 1:
The least common multiple of 330; 65; 15 is 

Question 2:
Given seven numbers: 25; 17; 39; 43; 239; 1021; 1023.
The composite numbers are  
(Write numbers in order from the least to the greatest and use ";")

Question 3:
The common factors of 18 and 27 are 
(Write numbers in order from the least to the greatest and use ";")

Question 4:
Given the set of even numbers: {2; 4; 6; …; 100}.The number of elements is 

Question 5:
Find four integer numbers a,b,c,d such that
a + b + c + d = 1
a + c + d = 2
a + b + d = 3
a + b + c = 4
Answer: (a;b;c;d)=() 

Question 6:
Find a four-digit natural number that is less than 2015.If the thousands digit is erased,the number will be decreased by 9 times. 
Answer:The number is 

Question 7:
Calculate: 1×2+2×3+⋯+100×101=

Question 8:
The  term of the expression A=1-7+13-19+25-31+⋯ is 

Question 9:
Given the expression A= ...
Find the value of n such that 2A+3=
Answer: n=

Question 10:
A natural number has six digits and the units digit is 4.If the units digit is moved to the first row then the number will be increasedby 4 times.The number is