A is an odd number, B is an even number, the following result is that the odd number formula is () A. 3a+bB. 2a+bC. 2（a+b）

A is an odd number, B is an even number, the following result is that the odd number formula is () A. 3a+bB. 2a+bC. 2（a+b）

A. A is odd, then 3a is odd, B is even, odd + even = odd, which conforms to the meaning of the problem; B. because 2a is even, B is even, even + even = even, which does not conform to the meaning of the problem; C. according to the definition of even, 2 (a + b) must be even, so it does not conform to the meaning of the problem

11 + 12 + 13 +... + 2010 + 2011 + 2012, whether the result is odd or even should have a formula
1 + 2 * 3 + 4 * 5 + 6 * 7 +... + 100 * 101 formula

Odd + odd = even, even + even = even, even + odd = odd
The sum of bits 0 to 9 is 5 groups of even + odd numbers,
11 + 12 + 13 +... + 2010 + 2011 + 2012 is (2012-10) / 2 = 1001 even + odd, the result is even

300+301+302+…… +Is the result of 397 odd or even
There's another 151 + 152 + 153 +. + 190 + 191, both

Even number one, odd number two. If you don't understand, ask

Is the result of formula (1 + 2 + 3 + 4 +... 99 + 100) * (1 + 2 + 2 + 3 + 3... + 11) odd or even?

Because 1 + 2 + 3 + 4 +... 99 + 100 = (1 + 100) × 100 △ 2 = 5050 is even
According to even × even = even
Even × odd = even
So whether the other factor is odd or even, the result is even

Two different natural numbers, one is odd, the other is even. Their greatest common factor is () and their least common multiple is ()

Two different natural numbers, one is odd, the other is even. Their greatest common factor is (1), and their least common multiple is (their product)

The product of two continuous odd numbers plus the larger one is the product of the even number sandwiched between the two continuous odd numbers and the larger odd number
We need to prove it

Let two consecutive odd numbers be 2N-1, 2n + 1
The product of two consecutive odd numbers plus the larger one
=(2n-1) (2n + 1) + 2n + 1 = (2n + 1) (2n) [extract common factor 2n + 1]
2n is the even number sandwiched between these two consecutive odd numbers
The larger odd number is 2n + 1
It's over

If both numbers are odd, is the sum of the two odd numbers odd or even? What is the difference between the two numbers? The product of the two numbers?

Odd + odd = even
Odd odd = even
Odd * odd = odd

17 times a prime number, the product must be () a, odd number B, prime number C, even number d, composite number

D
A composite number is a natural number which can be divisible by other numbers besides 1 and its own number. Obviously, the product can be divisible by 17 and the result is prime (1 is not prime)
Take counter examples: 17 × 2 = 34 even, composite 17 × 3 = 51 odd, composite
In this way, you can also choose D

The product of even times odd may be even or odd

No, it must be even

The product of the sum of three odd numbers multiplied by an even number is () 1 odd number 2 even number

2