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The prime numbers within 20 have (), the sum of them is (), and the total number has ()
The prime numbers within 20 are (2,3,5,7,11,13,17,19), the sum of them is (77), and the total number is (4,6,8,9,10,12,14,15,16,18,20)
If the number within 20 is a prime number and a composite number, there are two
Children: prime number and composite number are two opposite concepts. It is impossible to have a number that is both prime number and composite number
Within 20, there are only numbers that are neither prime nor composite numbers, which are 1
Prime numbers: 2, 3, 5, 7, 11, 13, 17, 19
Total number: 4, 6, 8, 9, 10, 12, 14, 15, 16, 18, 20
A natural number is either even or odd, or prime or composite
A natural number is either even or odd, or prime or composite (wrong)
1 is neither prime nor composite
0 is neither prime nor composite
From 11 to 20, the difference between the sum of all prime numbers and composite numbers is (). 3 = 1 and 4 parts () = () divided by 2 = how many parts 15 = 2 and how many parts 13?
From 11 to 20, the difference between the sum of all prime numbers and composite numbers is (35)
3 = 1 / 4 (8) = (6) divided by 2 = (5) 15 = 2 / 13
The multiple of 13 is ()
A. Composite B. prime C. may be composite or prime
The number of multiples of a number is infinite. The smallest multiple is itself. 13 is a prime number. Its smallest multiple is 13. Other multiples are composite numbers. Therefore, the multiples of 13 may be composite numbers or prime numbers
RELATED INFORMATIONS
- 1. The sum of two prime numbers is not only a multiple of 11, but also an even number less than 50
- 2. Is 209 prime or composite? If it is a composite number, please decompose it into prime factors
- 3. Which of the following numbers are prime numbers? Which are composite numbers? Please decompose the composite numbers into prime factors: 23, 32, 47, 65, 71, 78, 93 Let's say that 2 is equal to 1 × 2
- 4. 1、 The divisor of 1.54 is (), in which the odd number is (), the combined number is (), the prime number is (), and the even number is () 2. "2 / 3 of 12 chickens", here () is regarded as unit '1'. 2 / 3 means that the unit '1' is divided into () parts averagely, taking () parts, and "2 / 3 of 12 chickens" is () chickens 3. Three continuous natural numbers, the middle one is a, and the other two are (), () The greatest common divisor of 4.20 and 24 is () and the least common multiple is () In 5.1 and 4 / 5, there are () 1 / 5, and 8 1 / 4 are () 6. The unit of fraction is 1 / 4. The sum of all true fractions is () 7. Fill in the appropriate unit name or number in brackets 86 CC = 0.086 () 1.8 m3 = () l 8. The maximum three digits divisible by 2, 5 and 3 at the same time are () 9. Fill in a number in 324 () so that the number has a factor of 2, a multiple of 5, and can be divided by 3 2、 Judgment questions 1. If a number can be divided by 15, it must be divided by 3 and 5 at the same time 2. The fraction whose numerator is less than the denominator is true, and the fraction whose numerator is greater than the denominator is false 3. Multiply or divide the numerator and denominator of a fraction by the same number (except zero), and the unit of the fraction remains unchanged 4. The volume of a 400 cubic centimeter thermos cup should be smaller than 400 ml 5. Both a and B are natural numbers. If a △ B = 7, then the greatest common factor of a and B is 7 6. Fractions with the same denominator can be added or subtracted directly because their fractional units are the same 3、 Practical questions 2. Xiaohong's family bought a new goldfish tank with a side length of 4 decimeters on the bottom and 30 liters of water. How deep is it? 3. Two cuboids of equal volume are stacked to form a cuboid with a height of 12 cm. What is the surface area of the cuboid? What is the surface area of the newly stacked cuboid?
- 5. A natural number, if not prime, must be a composite number______ (judge right or wrong)
- 6. What are prime numbers, composite numbers and natural numbers
- 7. Natural numbers (except 0) are either prime numbers or composite numbers______ (judge right or wrong)
- 8. For a three digit number, the number on the hundred is a composite number and an odd number, the number on the ten is a prime number and an even number, and the number on the one digit is neither a prime nor a composite number What are the three digits?
- 9. What is the sum of the smallest composite number and the number that is neither prime nor composite?
- 10. A number () is called prime. A number () is called composite
- 11. The greatest common divisor of two positive integers is 6, and the least common multiple is 90 Why is the answer two,
- 12. If the greatest common factor of two numbers is 16 and the least common multiple is 480, and the difference between the two numbers is 16, what are the two numbers?
- 13. The greatest common divisor of two numbers is 6 and the least common multiple is 108. The sum of two numbers is 66. These two numbers are () ()
- 14. The greatest common divisor of two numbers is 6, the least common multiple is 108, where the number is 12, find another number
- 15. It is known that the least common multiple of two numbers is 60. The greatest common factor is 5. One of the numbers is 20. What is the other number?
- 16. It is known that the difference between two natural numbers is 3, and the product of their greatest common divisor and least common multiple is 180
- 17. The two greatest common factors are 12 and the least common multiple is 60. What are these two numbers
- 18. Given that the greatest common divisor of a and B is 15 and the least common multiple is 90, what are the two numbers? Explain the method, not just the answer
- 19. Divide the least common multiple of a and B by their greatest common divisor. The quotient is 12. If the difference between the two numbers is 18, find the two numbers
- 20. The quotient of the least common multiple of a and B divided by their greatest common divisor is 12, and the difference between a and B is 18