Question

The following statement is a correct argumentation:

13 is prime, since divisible by 3
21 is prime, since divisible by 3
23 is prime, since not divisible by 3
25 is not prime, since divisible by 5
7 is prime, since not divisible by 2, 3, 4, 5 and 6

Answer 1

False
True
True
True
True

Answer 2

Wow sorry the second one is False.

Answer 3

3 is false. 23 is prime, but not because its not divisible by 3. It's because it's not divisible by any integer before it except 1.

Answer 4

I agree Xavier, but the statement depending on how you take it is true.

Answer 5

I'm taking the format as: Statement, Reason.

Answer 6

I can agree then. 3 would be false.

Answer 7

The following product is a complete decomposition into prime factors:

12 = 2 × 2 × 3
14 = 2 × 7
16 = 4 × 4
42 = 6 × 7
42 = 2 × 3 × 7
63 = 3 × 21

Answer 8

Yes gthug that is correct

Answer 9

Well 16 woudl be 2 * 2 * 2 * 2

Answer 10

63 would be 3 * 3 * 7