The first 1, seven different prime numbers, their sum is 60, and the smallest prime number is (). 2. There are three prime numbers, A, B and C. It is known that A plus B equals C, and A is greater than B, then B must be ().
3. There are three consecutive natural numbers whose average can be divisible by three different prime numbers. What is to minimize the sum of these three natural numbers?
4. It is known that A×B+3=x, where a and b are prime numbers less than 1000 and x is odd. So what is the value of x?
5. Divide 99 by the sum of 19 prime numbers. The bigger the prime number, the better. What is this prime number?
6. How many ways can1999 be expressed as the sum of two prime numbers?
7. The sum of two prime numbers is 200 1. What is the product of these two prime numbers?
8. If an integer has both properties.
The difference between (1) and 1 is a prime number.
(2) The quotient of this number divided by 2 is also a prime number.
(3) The remainder obtained by dividing this number by 9 is 5.
We call this integer a lucky number, so what is the lucky number in the two-digit number?
9. There is a cuboid, and the sum of its front and upper areas is 209. If its length, width and height are prime numbers, what is the volume of this cuboid?
10 and four identical bottles are filled with a certain amount of oil, and each bottle and other bottles are weighed once. The recorded kilograms are as follows: 8, 9, 10,1,12, 13. It is known that the sum of the weights of four empty bottles and the sum of the weights of oil are prime numbers. How much oil does the heaviest two bottles have?
extreme
1, in a single-digit natural number, what is both odd and composite? What is neither a composite number nor a prime number? What is both even and prime? 2. What is the smallest sum of prime numbers in1~100?
3. The product of the sum and difference of two natural numbers is 4 1, so what is the product of these two numbers?
4. If the sum of all prime factors of 232323 is expressed as AB, then A×B×AB=?
The product of three consecutive natural numbers is 17 16. What are these three natural numbers?
6. If a natural number has four different prime factors, what is the smallest one?
7. What is the sum, difference, product and quotient of a number and its own addition, subtraction, multiplication and division?
8. The host said to the guest, "There are three children in the yard. The product of their ages is equal to 72, and the sum of their ages happens to be the building number of my home. Can you find out the age of these children? What is the building number of the host family?
9. There are 10 prime numbers today:17,23,314 1, 53,67,79,83,10/,/kloc. If we divide them into
10, four identical bottles are filled with oil, and each bottle and other bottles are weighed once, and the weights are respectively: 8, 9, 10,1,12, 13. It is known that the sum of the weights of four empty bottles and the sum of the weights of oil are prime numbers.