In natural numbers 1 to 10, the numbers that are both prime numbers and even numbers are prime numbers______ A number that is both a combined number and an odd number is______ .

In natural numbers 1 to 10, the numbers that are both prime numbers and even numbers are prime numbers______ A number that is both a combined number and an odd number is______ .

In natural numbers 1 to 10, the number that is both prime and even is 2, and the number that is both composite and odd is 9
Among the 20 numbers 1 &; 20, what are the prime numbers and the total numbers?
Prime: 2.3.5.7.11.13.17.19, composite 1.4.6.8.9.10.12.14.15.16.18, 1 is neither composite nor prime
Prime numbers within 10, composite numbers. Prime numbers within 20, composite numbers
How many prime numbers are there within 10? What are they
How many prime numbers are there within 20? What are the differences
Prime: 2.3.5.7
Total: 4.6.8.9.10
Within 20
Prime: 2.3.5.7.11.13.17.19
Total: 4.6.8.9.10.12.14.15.16.18.20
Class 10: prime number 2 3 5 7
Total: 4 6 8 9 10
① Prime: 2,3,5,7; composite: 4,6,8,9 (if 10 is included, so is 10)
② Prime: 2,3,5,7,11,13,17,19; total: 4,6,8,9,10,12,14,15,16,18 (if 20 is included, so is 20)
Prime numbers within 10 are 2, 3, 5, 7; combined numbers are 4, 6, 8, 9, 10
The prime numbers within 10 are 2, 3, 5, 7, 11, 13, 17, 19; the total numbers are 4, 6, 8, 9, 10, 12, 14, 15, 16, 18, 20
What is prime sum
Prime numbers are numbers that can't be divided completely except one and itself, such as 2, 5, 7, etc. composite numbers are numbers that can be divided completely except one and itself, such as 6, 8, etc
What is the difference between the sum of all prime numbers in 1 ~ 14 and the sum of composite numbers?
（2+3+5+7+11+13)-（4+6+8+9+10+12+14）=41-63=-22
It looks like the reverse
（4+6+8+9+10+12+14）-（2+3+5+7+11+13)=22
What are prime numbers and composite numbers
·Prime number: in all integers larger than 1, except 1 and itself, there is no other divisor. This kind of integer is called prime number or prime number
Composite number: the divisor of a number has other divisors besides 1 and itself, which is called composite number
What are prime numbers and composite numbers
Be more detailed
Prime numbers are numbers that can only be divided by themselves and one
Sum numbers are numbers that can be divided by other numbers besides one and oneself
Like 12
12=3*4
12=2*6
12=1*12
But 13 = 1 * 13
So 13 is prime and 12 is composite
The numbers here are all numbers in the range of positive integers
And 1 is neither prime nor composite
What are prime numbers and composite numbers
Prime number
Prime number is also called prime number. It refers to the number in a natural number greater than 1 which can not be divided by other natural numbers except 1 and the integer itself. In other words, a natural number with only two positive factors (1 and itself) is a prime number
The smallest prime number is 2, which is also the only even prime number. The first prime numbers are 2, 3, 5, 7, 11, 13, 17, 19, 23, 29 and 31
Total number
Numbers larger than 1 but not prime are called composite numbers
1 and 0 are neither prime nor composite
A number that can be divisible by other numbers in addition to 1 and the number itself
For example, 6 can be divided by 1 and 6, and also by 2 and 3
4,6,8,10,12,14,16,18,20,22,24,26,28,30.
What do prime numbers and composite numbers mean?
Prime numbers are also called prime numbers. In a natural number greater than 1, except for 1 and the integer itself, it cannot be divided by other natural numbers. In other words, natural numbers with only two positive factors (1 and itself) are prime numbers. Numbers larger than 1 but not prime numbers are called composite numbers. 1 and 0 are neither prime nor composite numbers. Composite numbers are obtained by multiplying several prime numbers. Therefore, prime numbers are the basis of composite numbers, There is no composite number without prime number. This also shows that the prime number mentioned above plays an important role in number theory. In history, 1 was also included in prime number, but later, for the sake of basic theorem of arithmetic, 1 was finally excluded from prime number by mathematicians. From the perspective of higher algebra, 1 is the unit element of multiplication, and it can not be included in prime number, All composite numbers can be obtained by multiplying several prime numbers
When a is 1, 2, 3, 4 and 5, is 6A + 1 prime or composite?
When a = 1, 6a + 1 = 6 × 1 + 1 = 7 is prime; when a = 2, 6a + 1 = 6 × 2 + 1 = 13 is prime; when a = 3, 6a + 1 = 6 × 3 + 1 = 19 is prime; when a = 4, 6a + 1 = 6 × 4 + 1 = 25 is composite; when a = 5, 6a + 1 = 6 × 5 + 1 = 31 is prime. Answer: when a = 1, 2, 3, 5, 6a + 1 is prime; when a = 4, 6a + 1 is composite