In natural numbers 1 to 20, there are prime numbers, composite numbers, odd numbers, even numbers, divisible by 2 and 3, divisor 2 and 5?

In natural numbers 1 to 20, there are prime numbers, composite numbers, odd numbers, even numbers, divisible by 2 and 3, divisor 2 and 5?

In natural numbers 1 to 20:
There are eight primes (2,3,5,7,11,13,17,19)
The total number is 11 (4,6,8,9,10,12,14,15,16,18,20)
Note: 1 is neither prime nor composite
There are 10 odd numbers (1,3,5,7,9,11,13,15,17,19)
There are 10 even numbers (2,4,6,8,10,12,14,16,18,20)
Three (6,12,18) can be divisible by two and three at the same time
There are two (10,20) with factors 2 and 5

In a mathematical problem, two natural numbers are divided. The divisor is the smallest composite number. The quotient is a single digit that can be divided by 2 and 3 at the same time. The remainder is 1.5 times more than the smallest prime number
The division formula is () △ () = () （）

The smallest composite number is 4, the smallest prime number is 2, so the remainder is 2 + 1 = 3, and the smallest one that can be divided by 2 and 3 at the same time is 6, so the division formula is 27 △ 4 = 6 three

Write three digits divisible by 2.3. And 5 at the same time with the smallest composite number, the smallest prime number and 0
What is the difference between the largest three digits and the smallest three digits?

Minimum composite 4, prime 2
From the meaning of the title, find the multiple of 30
Maximum 420
Minimum 240, phase difference 180

How many natural numbers have 8 divisors within 100? What is the smallest number?

Since 2 * 2 * 2 = 8, all natural numbers with 8 divisors have and only have three different prime factors
Included in 100
2*3*5=30
2*3*7=42
2*3*11=66
2*3*13=78
2*5*7=70
That is to say, the smallest of the above five is 30

The minimum multiple of a natural number is 18. There are () divisors of this number

6. 1.2.3.6.9.18

A is a natural number. The maximum divisor of a is ()? The minimum multiple is ()?

A is a natural number, the maximum divisor of a is (a) and the minimum multiple is (1)

There is a natural number whose single digit is zero. It has eight divisors. What is the minimum number?

According to the analysis, because 8 = 7 + 1 = (1 + 1) × (3 + 1) = (1 + 1) × (1 + 1) × (1 + 1), and because this natural number must contain two different prime factors, 2 and 5, and the minimum requirement, 8 can only be written as: (1 + 1) × (1 + 1) × (1 + 1); therefore, this natural number should be: 2 × 3 × 5 = 30; answer: the minimum natural number with zero digits and eight divisors is 30

A natural number has eight divisors. By adding the eight divisors, the minimum sum of divisors is 4 and the maximum sum is 140. What is the natural number?

The smallest divisor must be 1, so 4 = 1 + 3, and the second smallest divisor is 3
The largest divisor is itself, and the second largest divisor is the number divided by 3
140 / 4 = 35, so 140 = 105 + 35
The number is 105 = 3x5x7

The smallest multiple of a natural number () its largest divisor
Please help! Please elaborate!

The smallest multiple of a natural number is equal to its largest divisor
The smallest multiple of a natural number is itself, and its largest divisor is itself

A number is the continuous product of 5 2, 3 3, 2 5, 1 7. Of course, there are many divisors of this number which are two digits. Among these divisors, what is the largest?

97 is not a divisor of a, and 96 = 2 × 2 × 2 × 2 × 3 is a divisor of a, so the largest two digit divisor is 96